1 / 10

Main

Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Main. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it.

gerard
Download Presentation

Main

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. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Main

  2. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Top left Quartz Quartz is a crystal form of silicon dioxide (Si02), and grows in a 6-sided prism ending in a 6-sided pyramid. Smoky quartz The colour of smoky quartz is thought to come from either iron impurities, titanium impurities or irradiation. It’s relatively common.

  3. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Top mid Quartz Quartz is a crystal form of silicon dioxide (Si02), and grows in a 6-sided prism ending in a 6-sided pyramid. Citrine The colour of citrine is thought to come from iron impurities or irradiation. Relatively rare in its natural form, it’s more common for a citrine to actually be a heat-treated amethyst.

  4. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Top right Quartz Quartz is a crystal form of silicon dioxide (Si02), and grows in a 6-sided prism ending in a 6-sided pyramid. Amethyst The colour of amethyst is thought to come from iron impurities or irradiation. This deep violet colour is quite rare.

  5. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Center left Garnet Garnets are a group of minerals varying in the general formula X3Y2(SiO4)3. The crystal structure is usually dodecahedral (12-faced) although it can also be cubic (6-faced). Pyrope (“Red Garnet”) Pyrope is a magnesium-aluminium silicate - Mg3Al2(SiO4)3. It is formed in high-pressure rocks.

  6. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Center mid Garnet Garnets are a group of minerals varying in the general formula X3Y2(SiO4)3. The crystal structure is usually dodecahedral (12-faced) although it can also be cubic (6-faced). Rhodolite Rhodolite is a variety of Pyrope with a “rosy” colour. It can easily be mistaken for the more valuable Pink Tourmaline.

  7. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Center right Garnet Garnets are a group of minerals varying in the general formula X3Y2(SiO4)3. The crystal structure is usually dodecahedral (12-faced) although it can also be cubic (6-faced). Spessartite Spessartite is a manganese aluminium garnet - Mn3Al2(SiO4)3. It was first found in Spessart, Germany. There are only a few places in the world where this gem occurs.

  8. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Bottom left Tourmaline The group of minerals called tourmalines some of the most chemically complicated silicates. The constituent elements vary to give a wide variety of colours. Blue-green As with many types of tourmaline, blue-green tourmaline is dichroic – depending on the viewing angle, it appears either blue or green. The colour is thought to be due to traces of chromium and copper.

  9. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Bottom mid Tourmaline The group of minerals called tourmalines some of the most chemically complicated silicates. The constituent elements vary to give a wide variety of colours. Yellow The colour of yellow tourmaline is thought to be due to traces of magnesium. It is found in Malawi and Zambia.

  10. Semi-precious gems Here are a few semi-precious gems from the quartz, garnet and tourmaline families. Click a stone to find out more about it. Bottom right Tourmaline The group of minerals called tourmalines some of the most chemically complicated silicates. The constituent elements vary to give a wide variety of colours. Pink Pink tourmaline is a variety of Rubellite (deep red) which in turn is a variety of Elbaite- Na(Li1.5,Al1.5)Al6Si6O18(BO3)3(OH)4.

More Related