Epidote (silicates): benitoite
Diagnostic Card.
On the picture. benitoita crystals County of San Benito (California).
Ba Ti Si 3 O 9
Crystal system hexagonal
6.5 Hardness
Specific weight 3,65-3,7
Cleavage is absent
fracture conchoidal
Color blue or colorless, different-colored
Color white powder
Gloss glass
Named only until the discovery in San Benito (Calif.). It is found only in small crystals. It is easy to be confused with a sapphire. Pleochroism: very strong, colorless, greenish-blue - blue.
Benitoite - a rare gem of a beautiful, blue, much less - pink, white or colorless. Sometimes he has a pronounced zoning. The reason for the color change is the iron impurity. The crystals have a typical bipyramidal shape, triangular in cross-section; they are flattened along the vertical axis is very common. Generally transparent, have a glass luster. Benitoite - mineral pretty solid, moderately fragile, with conchoidal fracture.
Diagnostic features.
The main characteristic of this gem is a strong pleochroism, which is observed without the use of technical means. Crystal in different directions can then look blue, then colorless. In addition, benitoite has a typical blue fluorescence in shortwave ultraviolet light.
Place of Birth.
Unique deposit benitoita suitable for jewelery purposes, located in the State of California, County of San Benito. Benitoite enriched zeolites formed in hydrothermal veins, which are located among the micaceous schist in contact with serpentinized rocks. Rare instances of this mineral found in Texas and Belgium.
The use in jewelry.
elongation direction in which benitoita crystal has a beautiful blue color, does not coincide with the direction of flattening. This feature does not allow the best use in cutting (usually steps) crystals gem entire volume, which in nature are typically small in size. Benitoite - a rare mineral, as if specially designed by nature for jewelry purposes.
Benitoite. Origins p. San Benito, California, USA. Photo: © AA Evseev.
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Catalog minerals and gems in groups of the world
** - Poisonous stones and minerals
** - Radioactive rocks and minerals
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