1 / 14

Systematic Mineralogy

Learn how minerals are systematically divided into groups based on anions and structures. Explore the classifications like class, family, group, series, and species in mineralogy, with an example of Ca-grunerite.

ealexander
Download Presentation

Systematic Mineralogy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Systematic Mineralogy • Description of how minerals are divided into groups • Groups based on anions • Single anion (Cl-) • Anion group (SiO44-) • Further divided based on structures

  2. Divisions • Class (anion division) • Family (structural division – silicates mostly) • Group (structural division) • Series (solid solution) • Species (individual minerals) • Varieties (substituted elements)

  3. Example • Ca-grunerite: • A Ca-rich variety • Of a mineral species • In the cummingtonite-gruneriteseries • Of the amphibole group • Of the inosilicatefamily • Of the silicate class

  4. Silicates • The most common group of minerals forming Earth’s crust • 25% of all minerals (~1000) • 40% of rock forming minerals • 90% of earth’s crust – i.e., those minerals you are likely to find

  5. Silicate Structure • Basic building block: silica tetrahedron • Si4+ with four O2- surrounding it • Net charge is 4- • Mesodesmic, polymerization • Tetrahedron can share oxygen atoms

  6. Fig. 11-1 Silica Tetrahedron

  7. Six groups of silicate minerals • Orthosilicates = Nesosilicates • Single tetrahedron • Disilicates = Sorosilicates • Two tetrahedrons share single oxygen • Ring silicates = Cyclosilicates • 4, 5, or 6 tetrahedron share two oxygen

  8. Chain silicates = Inosilicates • 2 or 3 oxygen shared, arranged in single or double chain • Sheet silicates = Phyllosilicates • 3 oxygen shared in sheets • Framework silicates = Tectosilicates • All 4 oxygen are shared

  9. Ortho- (Neso) Fig. 11-2 Chain – double and single (Ino) Di- (Soro) Ring (Cyclo) Framework (Tecto) Sheet (Phyllo)

  10. Z/O ratios • Z = Si tetrahedral sites • Can be other cations, most commonly Al • Z/O ratio depends on type of silicate • Ortho = 1/4 • Di = 2/7 • Ring = 1/3 • Chain, single = 1/3; double = 4/11 • Sheet = 2/5 • Framework = 1/2

  11. Other ions • Quartz (and polymorphs) only minerals with only Si and O • All other silicates are charge balanced by other cations • “glue” that holds together silica tetrahedron

  12. Degree of polymerization depends on availability of Si • Quartz and feldspars (framework): Si-rich environments • Si/O = ½ • Olivine (orthosilicate): Si-poor environment • Si/O = ¼

  13. MaficvsFelsic • Mafic – rich in Magnesium and Iron (Ferrum), Si-poor • E.g. biotite, amphiboles, pyroxenes, and olivine • Commonly dark colored • Felsic – rich in Si and Al • E.g. Feldspars, Quartz (SiO2), muscovite, feldspathoids • Commonly light colored

More Related