Datolite is a mineral with a hardness of 5 out of 10 on the Mohs scale of mineral hardness [?]. These Monoclinicly structured gems are made of diatomaceous silica, their full chemical compound being Ca(B,OH)SiO4.

Datolite is a semi rare silicate mineral of the gadolinite group. It appears as surface-growing, short and stubby, prismatic, large crystals. Its crystal structure is monoclinic, as it has two axes of unequal length inclined to each other, with the third lateral axis at a right angle to the plane that contains the other two.

Its aggregates are huge, granular, dense, fibrous, and has porcelaneous crusts. It has a vitreous to greasy luster, blue luminescence, and ranges from transparent to translucent. Colorless, yellow, green, and red crystals have been found.

It fuses easily into transparent glass, turning the flame green. It dissolves easily in acids, forming a silica gel,

It occurs in basic, igneous rocks, in metamorphic rocks, and occasionally in ore veins. It is a secondary mineral in cavities in basalt and serpentinites and hydrothermal deposits, associated with zeolites, prehnite, and calcite.

Deposits are found in Schwarzwald, Harz/Germany, Norway, Massachusetts, New Jersey (USA). Splendid crystals have been found at Andreasberg (Germany), Arendal (Norway), and in the Habachtal (Austria). It occurs at Alpe di Siusi and Riso (Bolzano), Serra dei Zanchetti (Bologna), and in chalcedony amygdales at Tizza (Alto Adige), all in Italy. It has also been found with copper in basalt flows in the Lake Superior region.

Other names for datolite are "dystome spar." Varieties of datolite include "botryolite," a radiating columnar mineral with a botryoidal surface; "sugar stone," a compact white to pink variety from Michigan usually cut cabochon.

Datolite's Metaphysical Properties: Datolite is used by many who believe it has the power to boost ones societal standing, as well as memory, and assistance in bonding with others.

The specific gravity [?] for Datolite is 2.95, it's refractive index [?] is 1.62-1.65, and it's double refraction [?] is 0.044.


Gem-quality datolite has come usually from the Lane quarry in Westfield, Massachusetts, and pale green specimens are found in Paterson, New Jersey (USA) and San Luis Potosi (Mexico).

Industrial Usages

When available in large amounts, datolite is used as an ore of boron. It is occasionally cut cabochon, faceted, or cut as a curio stone, and prized by collectors.

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RI or Refractive Index defines light's ability to move through the mineral or in a general sense, any material.

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