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MINERALS Lab SELF-DIRECTED STUDY NAME: _______________________________ (PRINT CLEARLY)

MINERALS Lab SELF-DIRECTED STUDY NAME: _______________________________ (PRINT CLEARLY) THIS IS DUE ON OR BEFORE _______________ DIRECTIONS

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MINERALS Lab SELF-DIRECTED STUDY NAME: _______________________________ (PRINT CLEARLY)

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  1. MINERALS Lab SELF-DIRECTED STUDY NAME: _______________________________ (PRINT CLEARLY) THIS IS DUE ON OR BEFORE _______________ DIRECTIONS There are twelve pages of information provided to you regarding mineral classifications. It should prove to be interesting to those who want to learn more about minerals. You may work with other students, but the answers to all questions are contained within these pages.

  2. A Brief Overview of the Structure of Silicate Minerals As we look closely, we will see that there are over 3500 existing minerals. There are various methods to classify them. One means is based on the chemical formulae which can tell us if the mineral is a carbonate, hydroxide, sulfate, phosphate, halide, oxide, native element or other silicate minerals. Since over 85 percent of the Earth’s crust is comprised of silicate minerals (some variation of Si02), we will examine silicate minerals more closely. Minerals can be defined based on their crystallography in which the nature of the crystal growth is examined based on the atomic structure of the mineral. Each mineral crystal has a geometric body that is defined by the order in which its atoms arrange themselves. For instance, salt (NaCl) has a cubic crystal structure, because the atoms of sodium and chlorine arranged themselves in rows alternating from one to another and growing in equal directions and equal distances. That is why salt forms cubes. Most minerals will have a defined crystal structure (opal is a silicate that is like glass, having no crystal structure). There are three axises, a, b and c. They may vary in length and angle to define. There is the isometric, hexagonal, tetragonal, orthorhombic, monoclinic and triclinic. Some crystal structures are provided for some of the minerals here, to show you the variation in some of the crystal structures of some of the silicate minerals. Silicate minerals have a similar type of development with alternating atoms in its crystal structure. But beyond this, we can define the silicate minerals in a special classification based simply on the silica tetrahedra that form the basic structure for these minerals. Silica forms a pyramid, or silica tetrahedra with 4 oxygen atoms and 1 silicon atom. This is the foundation for all silicate minerals. The differences are based on how these silica tetrahedra are linked to one another. NESOSILICATES The NESOSILICATES are ISOLATED or individual silica tetrahedra with additional atoms attached to them. Now lets look at some nesosilicates: olivine, garnet (pyrope and almandine are merely two of the garnets), kyanite and andalusite are a mere handful of this type of silicate mineral.

  3. OLIVINE – Magnesium Iron Silicate (AKA as the gem peridot) (Mg,Fe)2 SiO4 (ORTHORHOMBIC CRYSTAL SYSTEM) It is olive green to yellowish brown in color with stubby crystals. Two minerals of olivine are fosterite (Mg2SiO4) and fayalite (Fe2SiO4) that form a continuous solution series. A continuous solution series is where the mineral has the ability to be isostructural (same base structure with variations in the cations) to form a complete series of minerals of any intermediate composition. As fosterite will continue to form until the magnesium is depleted. Nearly all of the olivine found is fosterite (including the gem peridot). It is usually found in mafic and ultramafic intrusive or volcanic igneous rocks. Olivine is a predominant constituent in dunites (>90%), peridotites and is very common in gabbros and basalts. The mineral (fayalite) is found in high-temperature and regionally metamorphosed or contact metamorphosed rocks. It is a very common mineral, but gem quality amounts are less abundant. Gem quality olivine (peridot) is found in San Carlos, Arizona. The abundance of non-gem quality materials is used to extract magnesium. Olivine is meta-stable at the Earth’s Surface. This means that a bright-green piece of peridot may lose color due to the low temperature and pressure. It was formed at high temperatures and high pressure. NESOSILICATES (single silica tetrahedra) PYROPE – Magnesium aluminum silicate (AKA as garnet) Mg3Al2(SiO4)3 (ORTHORHOMBIC CRYSTAL SYSTEM) Dark red usually well formed crystals with no cleavage. It is found in peridotites and is sometimes found with diamonds. Good quality specimens are found in Arizona and New Mexico.

  4. ALMANDINE – Iron aluminum silicate (AKA as garnet) Fe3Al2(SiO4)3 (ISOMETRIC CRYSTAL SYSTEM) Bright red or dark red in color. It has no cleavage. It is a common mineral found in medium-grade metamorphic environments. Excellent samples come from California and Colorado. TOPAZ – Hydrous aluminum silicate Al2SiO4(F,OH)2 (ORTHORHOMBIC CRYSTAL SYSTEM) Prismatic crystals with some as large as 500 pounds. Varies in color from colorless to yellow, blue, green and violet. Very hard (8 on Moh’s Scale) with perfect basal cleavage. Found in pegmatites, granites, and hydrothermal veins. Small colorless to pink crystals are abundant at Pikes Peak, Colorado. SOROSILICATES (two silica tetrahedra joined a the apexes) This group of silicate minerals develop with the apexes of the two silica tetrahedron connected. These are not as abundant as the previous group of minerals. EPIDOTE – Hydrous calcium aluminum iron silicate Ca2(Al,Fe)3Si3O12(OH) (MONOCLINIC CRYSTAL SYSTEM) Usually black or dark green in color. It is hard (6 to 7) and heavy. It is found in metamorphic rocks with a mafic composition, especially in the green schist facies. It is one of the few very common sorosilicates. It is found in Riverside, California. It is rarely used as a gemstone.

  5. SOROSILICATES (continued) ZOISITE – Hydrous calcium aluminum silicate Ca2Al3(Si3O12)(OH) (ORTHORHOMBIC CRYSTAL SYSTEM) This mineral is included in the epidote group. Colors vary from white, blue, pale green, pink and blue-violet. Found in high-temperature and high-pressure metamorphic rocks, hydrothermal veins and rarely at metamorphic contacts. Tiffany and Company marketed zoisite from Tanzania; the mineral’s only locality. It is a brown to green colored stone that with pressure and increase in temperature can be altered to the lovely blue-violet seen in the gem, Tanzanite. CYCLOSILICATES –These minerals have silica tetrahedra that form rings. BERYL- Beryllium aluminum silicate (AKA as Emerald) Be3Al2(Si6O18) (HEXAGONAL CRYSTAL SYSTEM) This mineral is usually found in association with pegmatites in Columbia and Africa. The limited amounts of Beryllium available helps attest to the mineral’s rarity. This mineral is famed by the well know and highly valued emerald. Emeralds are green while light blue is aquamarine, yellow is heliodor and pink is morganite. It has perfect basal cleavage and has a high occurrence of inclusions. These two properties help to make the stone easy to break despite its hardness of 7.5 to 8. TOURMALINE- Complex borosilicates (HEXAGONAL CRYSTAL SYSTEM) (Na,Ca) (Mg,Fe+2,Fe+3,Al,Mn,Li)3 Al6(BO3)3 (Si6O18) (OH,F)4 Elongated and striated crystals with a hardness of 7. There are six groups of tourmaline: schorl, elbaite, dravite, uvite, buergerite and liddiocatite. The mineral is piezoelectric and has been used in high pressure gauges. Elbaite is used as gemstones with dark red, rubellite, one of the most desirable varieties of tourmaline. Very common in pegmatites and in marbles. DIOPTASE – Hydrous copper silicate CuSiO2(OH)2 (HEXAGONAL CRYSTAL SYSTEM) Stubby bright green crystals with a hardness of 5. It is heavy and fragile. It is formed in the oxidation zone of copper deposits and cavities of copper minerals. Excellent specimens come from the Mammoth mine in Tiger, Arizona. It is valued by collectors and some jewelry makers.

  6. INOSILICATES – Form single chain tetrahedra like the pyroxenes or double chains like the amphiboles. Pyroxene Group - It is difficult to determine the pyroxene mineral in hand samples. Most analysis is done by spectrograph to determine the actual chemical composition of the rock to surmise the type of pyroxene. Basically we look at the environment in which the rock was formed and then try to determine the pyroxene. DIOPSIDE – Calcium magnesium silicate (AKA Pyroxene) CaMgSi2O6 (MONOCLINIC CRYSTAL SYSTEM) This is a very common mineral with prismatic crystals of green, blue, yellow or brown. It is frequently found in contact metamorphic rocks, particularly dolomitic marbles found with other calcium silicates. The heavy, almost square crystals often form from magnesium-rich metamorphic rocks. The mineral is used for collectors and in jewelry. Some of the diopside comes from Siberia. JADEITE – Sodium aluminum silicate (AKA as Pyroxene) Na(Al,Fe+3)SiO6 (MONOCLINIC CRYSTAL SYSTEM) Crystals are extremely uncommon. This mineral is heavy with a hardness of 6.5 to 7 with difficult cleavage. It is compact and varies in color from white, yellow, green to black. It is found in ultramafic rocks and is associated with nepheline. It has been found in metamorphic rocks which have undergone the blue schist facies. The term jade is used by the jewelry industry. Precious jade is jadeite. The dark or mossy green “jade” is nepheline, but is sold as jade. AUGITE – Calcium magnesium iron aluminum silicate (AKA as Pyroxene) (Ca, Na) (Mg, Fe, Al, Ti) (Si,Al)2O6 (MONOCLINIC CRYSTAL SYSTEM) This is a very common pyroxene. It is has a stubby almost square crystal habit like pyroxenes display and is black, greenish-black to a dark brown color. It is hard at 5-6 on the Moh’s Scale, and is common in plutonic rocks like gabbros, pyroxenites and peridotites. It is also associated with volcanic rocks such as basalts and tuffs, and high-temperature metamorphic rocks. Of interest to scientists to determine rock types. ENSTATITE – Magnesium silicate (AKA as Pyroxene) Mg2Si2O6 (ORTHORHOMBIC CRYSTAL SYSTEM) Good crystals are hard to find, despite that it is a very common mineral. It forms fibrous or platy minerals and is yellow, green or olive green in color. It has a hardness of 5.5 and is heavy, with good cleavage. It is common in mafic and ultramafic rocks, both plutonic and volcanic, and in high-grade metamorphic rocks. Good large crystals are found in Sierra Nevada, California.

  7. INOSILICATES - The silica tetrahedra form single chains in the pyroxenes and double chains as with the amphiboles. Amphiboles – Like the pyroxenes, there are several minerals that represent the mineral assemblage called amphiboles. The variation in chemistry makes it difficult to determine the specific type of amphibole. Again we look to spetrographic analysis to help us determine the type of amphibole based on the chemistry. Otherwise, we look at the environment in which the rock was formed and make an educated guess as to what type of we have found. One of the best methods to determine a blackened amphibole from a blackened pyroxene is to look for the sharp 120 degree angles on the amphibole crystals that are elongated with lines or striations running the length of the crystal. Pyroxenes are almost square and are often display a stubby crystal shape. TREMOLITE – Hydrous calcium magnesium silicate Ca2Mg5Si8O22(OH)2 (MONOCLINIC CRYSTAL SYSTEM) This mineral is white to gray in color. It has a hardness range of 5 to 6, and grows in long prismatic crystals. It is commonly known as abestiform amphibole (asbestos). It is found in dolomitic marbles and talc schists. It is a common mineral that is found in several located in several locations in the U.S. ACTINOLITE – Hydrous calcium magnesium iron silicate Ca2(Mg,Fe)5SiO22(OH)2 (MONOCLINIC CRYSTAL SYSTEM) Color is dark green (from the iron content) to a light green. It is common in mafic metamorphic rocks of the green schist facies and parts of the amphibolite facies. Good crystals are found in Wyoming. It is a very common mineral. HORNEBLENDE – complex silicate (Ca,Na)2-3(Mg,Fe+2,Fe+3,Al)5(Al,Si)8O22(OH)2 (MONOCLINIC CRYSTAL SYSTEM) This is an extremely common mineral with a variation in its chemistry depending on the available calcium, sodium and iron. It has perfect prismatic cleavage at 120 degrees. It is often found in metamorphic rocks of the amphibolite facies, and it is common in mafic and ultramafic igneous rocks. It is found various places in the U.S. PHYLLOSILICATES These are called sheet silicates because the silica tetrahedra form rings and rows that grow in two directions. The minerals usually have a flattened appearance and have thin layers or sheets that can be peeled back. That is because as one sheet is formed, it also grows upward with large atoms connecting the silica tetrahedra sheets together. These atoms form weaker bonds that allow the sheets to be peeled back in layers. The nature of the K (potassium) and Mg (magnesium) elements, shows why muscovite and biotite more easily peel back in layers, and why the talc atoms tend to slide across one another. Each mineral has layers of silica tetrahedra that grow in two directions.

  8. As the mineral grows upward, laying layer upon layer, the silica sheets are held together by atoms. Potassium is a large atom with an ionic radius of 1.38 angstroms, while magnesium has an ionic radius of .72 angstroms. The average atomic radius is .63 angstroms. So, the large potassium atoms holding the sheets will readily lose an electron, so it reaches the O level of the Noble Gasses. Magnesium is smaller and has to loose two electrons to reach the O level of the Noble Gasses. The potassium is more easily “satisfied” with the loss of one electron and has a larger radius, making the bond weaker than the magnesium atom. Therefore, the weaker potassium allows the sheets to be pulled apart in muscovite or biotite, while the magnesium atoms tend to slide across one another making the talc feel smooth or greasy. Common phyllosilicates that we will look at are: Talc, Muscovite, Biotite and Chrysocolla. TALC- Hydrous magnesium silicate Mg3Si4O10(OH)2 (MONOCLINIC CRYSTAL SYSTEM) This never forms in distinct crystals and is usually white, greenish-white or gray. It is soft with a hardness of 1 and has a greasy feel. It is very common and forms as an alteration product of magnesium silicates in ultramafic rocks. Occurs in various locations in the U.S. MUSCOVITE – Hydrous potassium magnesium silicate KAl2(AlSi3)O10(OH)2 (MONOCLINIC CRYSTAL SYSTEM) This is a very common mineral with tabular pseudo-hexagonal crystals. It occurs as a foliated and scaly laminar mass. It is silvery-white to dark brown. It is very common in plutonic rocks that are rich in silica and aluminum (usually granites and pegmatites). It is also found in metamorphic rocks that have gone through the green schist and amphibolite facies). Some crystals found in Canada are as large as 30 to 50 square yards in size. It obtained its name because the citizens of Moscow used large crystal sheets as windows. BIOTITE – Hydrous potassium aluminum silicate K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2 (MONOCLINIC CRYSTAL SYSTEM) This is a very common mineral that is usually found in small platy aggregates. It is soft with a hardness of 2.5 to 3. This mineral is found in many intrusive igneous rocks, some lavas, lamprophyres and metamorphic rocks. Large crystals to 76 square yards have been found in Russia. CHRYSOCOLLA – Hydrous copper silicate (Cu,Al)2H2Si2O5(OH)4. nH2O (MONOCLINIC CRYSTAL SYSTEM) This is an earthy massive microcrystalline mineral with a bright green to blue color. It is found in the oxidation zone of copper deposits and is associated with minerals such as: azurite, malachite and cuprite. It is a surface indicator showing the location of copper ore. It is found in the Clifton-Morenci districts in Arizona. A useful copper ore.

  9. TECTOSILICATES These silicate minerals have silica tetrahedra that grow outward in three dimensions. They include the quartz minerals, zeolites, sodalites and feldspars. These are generally common to very common minerals. QUARTZ – Silicon Dioxide SiO2 (HEXAGONAL CRYSTAL SYSTEM) This is one of the most common mineral of the earth’s crust at amount s around 12 percent per volume. It can form in plutonic, hypabyssal, and volcanic rocks. It can also crystallize from hot or cold solutions. There is clear quartz, milky quartz, rose quartz, blue quartz (fairly common in metamorphic rocks), citrine- yellow quartz, amethyst-purple quartz, tiger’s eye, aventurine- green quartz, chalcedony, only, jasper, onyx, carnelian, chrysoprase, heliotrope (bloodstone), flint and chert. Many of these varieties are used as semi-precious gemstones. FELDSPARS – These minerals are very abundant and are second in abundance, next to quartz, as a constituent in the earth’s crust. There are the alkali feldspars and the plagioclase feldspars. The alkali feldspars have high amounts of potassium and are typically pink in color. The plagioclase feldspars are rich in calcium and sodium, both elements helping to make these feldspars typically white in color. ALKALI FELDSPARS - SANIDINE, ORHTOCLASE, MICROCLINE and ORTHOCLASE Potassium aluminum silicate - KALSi3O8 Sanidine – typical of recent volcanic igneous rocks such as trachytes. It is also found in basalts. Orthoclase – this is a medium to high temperature feldspar that may form from the slow cooling of sanidine. It is found in granites, granodiorites, syenites and monzonites. It is found as a detrital mineral in arkose sedimentary rocks. Microcline- varies in color from white, pink, red, yellow and blue-green. It is found in granitic pegmatites and gneisses. (Green variety is amazonite used in jewelry.) Orthoclase- this is formed in low-temperature hydrothermal veins. There is an opalescent variety that is used in jewelry and is called moonstone.

  10. TECTOSILICATES FELDSPARS – These minerals are very abundant and are second in abundance, next to quartz, as a constituent in the earth’s crust. There are the alkali feldspars and the plagioclase feldspars. The alkali feldspars have high amounts of potassium and are typically pink in color. The plagioclase feldspars are rich in calcium and sodium, both elements helping to make these feldspars typically white in color. PLAGIOCLASE FELDSPARS – ALBITE, OLIGOCLASE, LABRADORITE, ANORTHITE Albeit – NALSi3O8 - Sodium aluminum silicate - This mineral is common in alkali plutonic igneous rocks such as granites, pegmatites and syenites. It is abundant, but not as abundant as the other plagioclase feldspars. Plagioclase, Labrador and amortize are all sodium calcium aluminum silicates (Na,Ca)AlSi3O8 These isomorphic minerals vary based on the amounts of calcium present. They are common in plutonic and volcanic rocks. As the rock becomes more mafic, the plagioclase will become more calico. FELDSPATHOIDS – Occur in rocks in lieu of feldspars because the solution was deficient in silica. The framework structure is (Si,Al)O4. If free silica is present a feldspar would form. A subgroup of feldspathoids is sodalite. Nepheline is one of the predominant feldspathoids that occurs in many alkaline igneous rocks and can occur when magma reacts with a limestone. Another familiar sodalite is lazuirte, which forms when limestone is metamorphosed. Lazurite is the major component of lapis-lazuli a dark blue sodalite often having traces of pyrite (lead sulfide). ZEOLITES – These are a large group of minerals which have a structure similar to feldspars and feldspathoids and have a very open framework of silica tetrahedra. The metal cations fill the large cavities in the structure that also contains loosely held water molecules. Most are colorless to white and form as a late-stage mineral in basic lavas. They are residual minerals after feldspar or feldspathoid alteration. Zeolites are found in volcanic rocks and sediments which have experienced very low-grade metamorphism which is called the zeolite facies. Some zeolites are natrolite, mesolite, scolecite, and laumonite.

  11. NON-SILICATE MINERALS These minerals include native elements, sulfides, sulfates, oxides and hydroxides, carbonates and halides. NATIVE ELEMENTS These minerals have one singular element as its composition. These are often found in hydrothermal veins, volcanic rocks, igneous rocks or in metamorphic rocks. They include: copper Cu, silver Ag, gold Au, mercury Hg, nickel-iron Ni,Fe (from meteorites), platinum Pt, arsenic As, antimony Sb, bismuth Bi, graphite C, diamond C and sulfur S. Excellent samples of native copper come from Bisbee, Arizona. Arsenic has been mined in Santa Cruz County, Arizona. Graphite and diamond are polymorphs. They each have the same chemical composition, but have different structural arrangements of the atoms. SULFIDES These minerals are similar in composition because they are typically some permutation of a metal with sulfur atoms. They differ from sulfates (SO42-) because there is no oxygen in sulfide minerals. These metals are copper, iron, silver, zinc, nickel, antimony, cadmium, lead, mercury, bismuth, gold, tellurium, manganese, cobalt and molybdenum. Some of these minerals are: Chalcocite – Cu2S (copper sulfide) Bornite - Cu5FeS4 (copper iron sulfide) Argentite – Ag2S (silver sulfide) Sphalerite – (Zn,Fe)S (zinc iron sulfide) very common Chalcopyrite – CuFeS2 (copper iron sulfide) very common Pyrrhotite - Fe1-xS (iron sulfide) very common Galena – PbS (lead sulfide) very common Cinnabar – HgS (mercury sulfide) Covellite – CuS (copper sulfide) Pyrite – FeS2 (iron sulfide) very common Marcasite – FeS2 (iron sulfide) a polymorph of pyrite – very common Realgar – AsS (arsenic sulfide) Orpiment – As2S3 (arsenic sulfide) Many of these minerals are an ore source for these metals. HALIDES These minerals include: halite (NaCl) and fluorite (CaF2) which are very common; sylvite (KCl), cryolite (Na3AlF) and other minerals in lesser amounts.

  12. OXIDES AND HYDROXIDES These contain and oxygen ion or a hydroxide or both in its composition. Cuprite – Cu2O (copper oxide) Found in the oxidation zone of copper deposits. Important copper ore. Spinel- MgAl2O4 (magnesium aluminum oxide) Used as a gemstone and is rather common. Found in dolomitic metamorphic rocks. Magnetite - (Fe+2Fe+32O4 (iron oxide) (AKA lodestone) The richest and most important iron ore, strongly magnetic, found in mafics and ultramafics. Chromite – FeCr2O4 (iron chromium oxide) The main ore of chromium found in mafic and ultramafic rocks. Chrysoberyl – BeAl2O4 (beryllium aluminum oxide) Source for the gemstone alexandrite, found in pegmatites, aplites and mica schists. Corundum – Al2O3 (aluminum oxide) It has no cleavage, a hardness of 9 and is the source for rubies and sapphires. Hematite – Fe2O3 (iron oxide) It is an abundant mineral and is very common in lavas and sedimentary rocks. Ilmenite – FeTiO3 (iron titanium oxide) The main ore for titanium is a common accessory in plutonic rocks. Rutile – TiO2 (titanium oxide) Important commercial ore of titanium and is often found in quartz veins. Cassiterite – SnO2 (tin oxide) Important ore of tin and is found in pegmatites. Pyrolusite – MnO2 (manganese oxide) An important ore of manganese is found as a sedimentary chemical rock. Uraninite – UO2 (uranium oxide) An important source for uranium usually found in sedimentary clastic rocks. Bauxite – FeO(OH) (hydrous aluminum oxide) Main ore of aluminum, found in subtropical sediments from silica and carbonate rocks. Goethite – FeOOH (iron hydroxide) Important iron ore commonly found in the hematite ore deposits of Lake Superior.

  13. CARBONATES These minerals have a carbonate ion (CO32-). The ones listed below are rather common carbonate minerals. Magnesite – (MgCO3) magnesium carbonate Smithsonite – (AnCO3) zinc carbonate Siderite – (FeCO3) (iron carbonate Rhodochrosite – (MnCO3) manganese carbonate Calcite – (CaCO3) calcium carbonate (polymorph of Aragonite) Dolomite – (CaMg(CO3) calcium magnesium carbonate Aragonite – (CaCO3) calcium carbonate (polymorph of Calcite) Azurite – (Cu3(CO3)2(OH)2 hydrous copper carbonate (found in Bisbee and Morenci, AZ) Malachite – (Cu2(CO3)(OH)2 hydrous copper carbonate (found in Bisbee, AZ) We noticed two polymorphs above, that is two minerals with the same chemical composition, but different structurally distinct forms. These are calcite and aragonite. SULFATES These minerals have (SO42-) sulfate ions in their composition. Many of them are common precipitates found in dry desert regions, where waters dissolve minerals and allow quick precipitation, especially in soils. Anhydrite – (CaSO4) calcium sulfate (a source for sulfur) Barite – (BaSO4) barium sulfate (the main barium ore) Anglesite – (PbSO4) lead sulfate (a lead ore) Brochanite – (Cu4(SO4)(OH)6 hydrous copper sulfate (significant copper ore, Bisbee, AZ) Linarite – PbCu(SO4)(OH)2 hydrous lead copper sulfate (Mammoth mine, Tiger, AZ) Chalcanthite – (CuSO4.5H2O) hydrated copper sulfate (found in southwest copper mines) Epsomite – (MgSO4.7H2O) hydrated magnesium sulfate (epsom salt) Gypsum – (CaSO4.2H2O) hydrated calcium sulfate These minerals that have been provided are merely a handful of the minerals that exist. The non-silicate minerals often form once a magma has been almost depleted, by hydrothermal fluids or other means.

  14. PHOSPHATES (Arsenates and Vanadates) These minerals have (PO42-) phosphate ions in their composition. Many of them are common precipitates found in dry desert regions, where waters dissolve minerals and allow quick precipitation, especially in soils. Apatite – A5(XO4)3(F,Cl,OH) A can be = Ca, Sr, Pb, Na, K X can be = P, As, V, Si This is a very common mineral as fluorapatite, chlorapatite, and hydroxylapatite). It is found in many environments including hydrothermal veins, iron-rich igneous rocks and marine sedimentary rocks. It is used for phosphates in fertilizers. Vanadinite - Pb5(VO4)Cl - Lead vanadate chloride This is a secondary mineral found in the oxidation zones of lead deposits. It is an ore of vanadium, used in metal alloys and in dyes. Excellent crystals have been recovered from the Old Yuma Mine in Arizona. Variscite - AIPO4.2H2O – Hydrated aluminum phosphate This is typically a pale green with fine crystalline masses. It is formed by the infiltration of phosphatic waters into aluminum rich rocks. It is an ornamental material polished and sold as turquoise. Turquoise – CuAi6(PO4)(OH)8.5H2O – Hydrated copper aluminum phosphate This usually occurs in masses and varies in color from light –blue to green. Found in the desert southwest. White turquoise is howlite and is not turquoise. Many green colored massive minerals are sold as turquoise. There have been excellent specimens from the Sleeping Beauty mine and the Kingman mines in Arizona.

  15. ANSWER THE FOLLOWING FROM INFORMATION GLEANED IN THE TEXT. • This is an example of a silicon tetrahedron. There are 4 ______________ atoms and 1 ___________ atom. This is the basic building block for ____________ which are the most abundant mineral group in the Earth’s crust. • This pyramid represents the _____________ ______________ with the points of the pyramid representing the ________________ atoms and the silicon atom not shown but is understood to be suspended in the center of the pyramid. • The structure of silicates is defined based on the number and arrangement of the atoms of oxygen and silicon. A single tetrahedron is representative of the ______________. Give one mineral that belongs to this silicate group and give its chemical formula: _____________________ ; _______________________. • These pyramids represent the next silicate group called the ________________. There are two silica tetrahedra joined at their apexes. Give a mineral that belongs to this group: __________________.

  16. These tetrahedra, joined in a circle, are an example of a ________________. Give an example of this type of silicate mineral: ___________________. 6. This is an example of a single chain silicate, also called __________________. One group of iron bearing minerals that you read about falls in this category of silicate minerals and is called: ___________________________. • The above represents double chain silicates, also called _________________. The large group of mafic minerals, minerals with high magnesium and iron content, are rather common and belong to this silicate classification, they are called ___________________________.

  17. A. The above arrangement of silica tetrahedra represent ___________ silicates. Of this group of silicates, name two minerals that belong to this classification group: _______________________ and ___________________________. • B. Why does talc feel greasy? • C. Why does muscovite allow for the sheets to be easily peeled apart? • The last group of mineral classification of silicates are the tectosilicates. Answer the following questions regarding this class. • A very abundant mineral assemblage belongs to this mineral group. Name two mineral groups that are tectosilicates: ________________________ and __________________________. • In what direction do tectosilicates grow? • Tectosilicates are rather durable or hard minerals. To what feature of these minerals could we attribute their strength?

  18. Cupric minerals are those containing copper. Arizona is called the copper state because it has several mineral sources for copper ores. Provide the name and chemical formula for 1 silicate and 2 sulfate minerals that are found in Arizona and contain copper. • A. ___________________ (name) ____________________ (formula) • B. ___________________ (name) ___________________ (formula • C. ___________________ (name) ___________________ (formula) • Provide two characteristics that all sulfides have in common: • A. ________________________________________________________________ • B._________________________________________________________________ • 12. Provide two sets of minerals that are polymorphs and define what a polymorph is. • A. _______________________ and _____________________ • B. _______________________ and _____________________ • C. A polymorph is:____________________________________ • ___________________________________________________ • ___________________________________________________ • ___________________________________________________. • From what minerals (give chemical formulae) are the following gemstones derived? A. Emerald _______________ formula __________________ • B. Alexandrite _______________ formula __________________ • C. Amethyst _______________ formula __________________ • D. Ruby ________________ formula __________________ • E. Jade ________________ formula __________________ • F. Garnet ________________ formula __________________ • G. Peridot _________________ formula __________________

  19. List the following minerals that are sources of ores for these elements: • A. Tin • mineral name: _____________________ and formula ____________________ • B. Chromium • mineral name: _____________________ and formula ____________________ • C. Titanium • mineral name: _____________________ and formula ____________________ • D. Uranium • mineral name: _____________________ and formula ____________________ • E. Aluminum • mineral name: _____________________ and formula ____________________ • F. Barium • mineral name: _____________________ and formula ____________________ • G. Lead • mineral name: _____________________ and formula ____________________ • H. Iron • mineral name: _____________________ and formula ____________________ • I. Copper • mineral name: _____________________ and formula ____________________ • J. Sulfur • mineral name: _____________________ and formula ____________________ • Hardness is an indicator of mineral durability. The harder the mineral, the less it can be scratched or worn down. Another indicator of durability is cleavage. Even though a diamond is harder than a ruby, the ruby is a more durable gemstone to wear in a ring than a diamond. Look at the cleavage of these minerals and explain: • A. Why the ruby is more durable than a diamond? • B. Why does the ruby have the same durability as a sapphire?

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