Dictionary.net

• A mineral, hard, brittle, and translucent, called by Hauy triphane. It occurs in laminated masses, easily divisible into prisms with rhomboidal bases; the lateral faces smooth, shining, and pearly; the cross fracture uneven and splintery. Before the blowpipe it exfoliates into little yellowish or grayish scales; whence its name. It is found at Uto in Sweden, in the Tyrol, in Ireland, and North America. It consists of silica and alumina, with 8 to 10 per cent of lithia, and a little protoxide of iron.

1899 - The american dictionary of the english language.
By Daniel Lyons