FELDSPAR: Albite, Sri Lanka (4.6), New Mexico (3.9). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Albite, usually colorless but sometimes yellow, pink, gray or reddish. Translucent albite is sometime colored green by chrome jadeite. It is also a component of trapiche emeralds.
Albite Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Albite Information
| Data | Value |
| Name | Albite |
| Is a Variety of | Feldspar |
| Varieties | Peristerite |
| Crystallography | Triclinic. Twinned; platy crystals. |
| Colors | Colorless, white, yellow, pink, gray, reddish, greenish. |
| Luster | Vitreous to pearly. |
| Luminescence | Usually none; may be whitish in LW, lime green in X-rays (Kenya). |
| Spectral | Not diagnostic. |
| Formula | Ab100, Ab90 |
Comments
Translucent albite is sometimes found that is colored a rich green by inclusions of chrome-rich jadeite. Albite is sometimes intergrown with emerald, especially in the strange hexagonal skeletal crystals known as trapiche emeralds. Facetable albite from Madagascar has indices: a = 1.530-1.531; β= 1.532-1.533; γ= 1.539-1.540; birefringence 0.009-0.010; density 2.62. Small faceted gems are fairly rare, almost always from the tips of cleavelandite crystals. Albite gems are colorless in most cases and not exciting to look at. Albite moonstones are known from many localities (discussed below).
Name
Albite comes from the Latin albus, meaning white, because the mineral is usually white.
Occurrence
Albite usually forms at low temperatures; it is common in pegmatites, granite, and other igneous rocks, various metamorphic rocks, also marbles.
- Essex County New York.
- Ontario, Canada; Quebec, Canada; Madagascar; Austria.
- Rutherford Mine, Amelia, Virginia: fine colorless albite, facetable, large; crystals are platy variety known as cleavelandite.
- Upson County, Georgia: moonstone.
- South Dakota: cleavelandite.
- Brazil: cleavelandite.
- Kenya: colorless crystals, some with blue or yellow tinge.
- (Indices: 1.535/1.539/1.544; S.G. 2.63). Many other localities worldwide.
Stone Sizes
Clean gems are usually in the 1-3 carat range, from cleavelandite crystals. Catseye gems up to about 50 carats are known.
- Royal Ontario Museum (Toronto, Ontario, Canada): 12.25 (catseye, Burma).
- Devonian Group (Calgary, Alberta, Canada): 11.13 (cateye, white).
