In gemology, any chrysoberyl that changes color can be called alexandrite. The nomenclarture is not dependent on the colors of the change. However, alexandrite's color change is dependent on pure light sources to be viewed correctly.
Faceted, Cat's-Eye
Alexandrite |
June's Birthstone |
Major Sources |
Brazil, India, Madagascar, Russia, Sri Lanka, & Tanzania |
Colors Found |
Teal, Blue-Green to Forest Green changing to Violet, Crimson Red, Raspberry, Purple and Orange |
Family |
Chrysoberyl: BeAl2O4 |
Hardness |
8.5 |
Refractive Index |
1.74 - 1.76; Biaxial (+ or -) |
Specific Gravity |
3.70 - 3.78 |
Crystal System |
Orthorhombic |
The pearl begins life as a foreign body (generally a parasite), which makes its way into the shell of marine or freshwater mollusk-usually oysters or clams. The mollusk's defense mechanism is to coat the intruder with layers of slightly iridescent substance, "nacre," which is the attractive outside of the pearl.
Freshwater, Tahitian, South Seas
Pearl |
June's Birthstone |
Major Sources |
Australia, Burma, China, Indonesia, Japan, Philippines, Tahiti & Vietnam |
Colors Found |
Black, Cream, Gold, Golden Yellow, Gray, Orange, Pink, Silver & White |
Family |
Organic |
Hardness |
2.5 - 4.5 |
Refractive Index |
1.52 - 1.66 |
Specific Gravity |
2.60 - 2.85 |
Crystal System |
N/A |
Moonstone is a potassium-rich arthociase member of the feldspar group of minerals and is closely related to sunstone and labradorite. The name feldspar comes from the German feldt spat, meaning "field stone."This is because when feldspar weathers, it releases large amounts of plant nutrients like potassium, which enrich the soil.itrine occurs naturally in proximity to amethyst and is a related quartz mineral. Its color is due to small amounts (approximately 40 parts per million) of iron in the crystal structure of quartz.
Gray, White, Orange, Rainbow
Moonstone |
June's Birthstone |
Major Sources |
Brazil, Burna, India, Madagascar, Sri Lanka, & Tanzania |
Colors Found |
Colorless to Brown, Green, Gray, Pink, Rainbow & Yellow |
Family |
Feldspar |
Hardness |
6 - 6.5 |
Refractive Index |
1.51 - 1.53 |
Specific Gravity |
2.56 - 2.59 |
Crystal System |
N/A |
©2011 America's Collectibles Network Inc. ♦ Gerald D. Sisk, JR. ♦ Guide to Gems & Jewelery ♦ Jewelry Television™