Amblygonite is a collector stone occasionally clean enough to be faceted. The most important sources for amblygonite are the deposits in Sao Paulo and Minas Gerais, Brazil. Amblygonite forms in large rough triclinic crystals with a tabular habit and perfect basal cleavage. The mineral is a fluophosphate which like topaz, has the fluorine replaceable by the hydroxyl group.
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Known Facts |
Color Key: |
Generally white or creamy, but can also be colorless or pale yellow, green, blue, beige, gray, brown or pink. |
Chemical Composition: |
(Li,Na)Al(PO4)(F,OH) |
Hardness: |
6 |
Density: |
3.015 – 3.033 |
Crystal Group: |
Triclinic |
Ocurrence: |
Brazil, U.S.A., France, Australia, Namibia |
Amblygonite is prismatic to columnar in form with good cleavage is in several directions. The fracture is irregular- uneven or sub-conchoidal. The luster is vitreous to pearly and faceted stones are very rarely clean. Amblygonite is biaxial and may be either positive or negative. The birefringence values range from .020 - .027 and pleochroism is weak or unobservable. Ultraviolet fluorescence may be a very weak green in long wave along with some light blue phosphorescence in long wave and short wave UV. |
Illustrations |
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