| Red beryl | |
|---|---|
 | |
| General | |
| Category | Cyclosilicate beryl |
| Formula (repeating unit) | Be 3Al 2Si 6O 18 with a mix of Mn3+ ions |
| Crystal system | Hexagonal |
| Space group | P6/mcc |
| Identification | |
| Color | Dark red |
| Twinning | Extremely rare |
| Cleavage | Indistinct |
| Fracture | Conchoidal |
| Mohs scale hardness | 7.5–8 |
| Luster | Vitreous |
| Streak | white |
| Specific gravity | 2.66–2.87 |
| Optical properties | Uniaxial (−) |
| Refractive index | 1.560–1.577 |
| Birefringence | δ = 0.0040–0.0080 |
| Dispersion | 0.014 |
| Ultraviolet fluorescence | None |
Red beryl, formerly known as bixbite and marketed as red emerald or scarlet emerald, is an extremely rare variety of beryl as well as one of the rarest minerals on Earth.[1][2]: 19 The gem gets its red color from manganese ions embedded inside of beryllium aluminium cyclosilicate crystals.[1] The color of red beryl is stable up to 1,000 °C (1,830 °F). Red beryl can come in various tints like strawberry, bright ruby, cherry, and orange.[3]
The largest crystals of red beryl are about 2 cm (0.79 in) wide and 5 cm (2.0 in) long. However, most crystals are under 1 cm (0.39 in) long.[1] Recently,[when?] the red variety of pezzottaite has been sold in markets as red beryl by some sellers.[4]
- ^ a b c "Red Beryl: One of the World's rarest gemstones – mined in Utah". geology.com. Retrieved 2021-08-30.
- ^ Grande, Lance; Augustyn, Allison (2009-11-15). Gems and Gemstones: Timeless Natural Beauty of the Mineral World. University of Chicago Press. ISBN 978-0-226-30511-0.
- ^ "Red Beryl gemstone information". www.gemdat.org. Retrieved 2021-09-21.
- ^ "Bixbite (Red Beryl)". National Gem Lab. 2017-03-04. Retrieved 2021-09-21.