Epidote usually occurs in a peculiar yellowish-green, called pistachio
green, a color that is seldom found in other minerals. Besides
this color, olive, brownish-green, greenish-black and black, red,
yellow-gray, and grayish-white occur. The hardness of epidote is 6
to 7; specific gravity, 3.32 to 3.50; lustre, vitreous to pearly;
refraction, double. The stone is transparent to opaque, is attacked by
acids, and is slightly affected by the blow-pipe. It is composed of:
Silica 38
Alumina 22
Ferric oxide 15
Lime 23
Water 2
Epidote is found in Norway, Saxony, Siberia, Brazil, on the St.
Gothard, in Switzerland, in the Tyrol, and in the Hartz.