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STAUROLITE
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This
mineral when sufficiently transparent to make a gem, furnishes a dark,
brownish red stone, not unlike some varieties of garnet in color. It is
similar also to garnet in hardness, 7-7.5, and specific gravity, this
being about 3.7. It differs, however, in crystallizing in the
orthorhombic system, and hence it is doubly refracting. The crystals
usually have the shape of six-sided prisms, often grouped in the shape
of a cross, the latter habit giving the mineral its name, from the
Greek, stauros,
a
cross. Groups of this shape are found abundantly in Fannin County,
Georgia, and are there known as fairy stones, under the belief that
fairies make them. The peasants of Brittany wear similar crystals as
charms, believing them of miraculous origin. The Penitentes of New
Mexico are said also to have great reverence for the stone, each member
of the sect being accustomed to wear one around his neck. A traveler
endeavoring to buy one found it impossible to do so, the owner saying
that he would sooner part with one of his children. The stone had been
blessed by the priest, and its possessor believed that it insured him a
long and happy life, and protected him from all ailments and accidents.
In
composition staurolite is a hydrous silicate of iron, magnesium, and
aluminum. It is generally infusible, and but slightly attacked by
acids. Rolled pebbles of staurolite occur in the gem gravels of Brazil,
and crystals suitable for cutting into transparent stones come from
SwitÂzerland and Moravia. Staurolite is a common mineral in mica
schists, and in such a matrix occurs in several localities in this
country, but no transparent crystals have been found here.
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