Table of Gems Ordered by Crystal System
This table contains a selection of minerals gemologists may encounter as jewelry stones or gem specimens. The gems are sorted by their crystal system.
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"Amorphous" gems have no crystal structure.
Selected Minerals by Crystal System
1. Boleite has also been classed as a tetragonal, pseudo-cubic crystal.
2. Synthetic, lab-created material.
3. May lose their crystalline structure due to radiation (metamictization).
4. In modern times, hyacinth or jacinth usually refers to reddish brown zircon, which belongs to the tetragonal crystal system. However, historically it has also been used to refer to hessonite (cubic), topazes (orthorhombic), and various other gemstones.
5. Mimetite has also been classed as a monoclinic, pseudo-hexagonal crystal.
6. Both natural and synthetic stones. (Natural moissanite crystals are too small to cut).
7. Any beryl variety not aquamarine, emerald, goshenite, heliodor, morganite, or red.
8. Many of the materials mineralogists have classed as trigonal crystals have been classed by gemologists as hexagonal crystals in a trigonal subclass. Thus, you'll find many of the gems listed here classed as hexagonal in their individual gem listings.
9. Wollastonite has monoclinic and triclinic polytypes.
Additional Crystal System Information
International Gem Society
Table of Refractive Indices and Double Refraction of Selected Gems
Properties of Diamond Simulants
Ring Size Comparison Chart
Weights and Measures Conversion Chart
What is the Best Lap for Polishing Sapphire?
Seven Famous Pearls and Their Histories
Opal Stones and Gems: Value, Price, and Jewelry Information
Seven Stunning but Delicate Engagement Ring Stones
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