Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/102

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TABLE OF THE MODIFICATIONS OF THE PRIMITIVE CRYSTAL OF THE LAUMONITE.

Primitive Crystal. A tetrahedral prism slightly rhomboidal of 92° 30′ and 87° 30′, with rhombic bases inclined on the edges formed by the meeting of the sides of the prism at an angle of 92° 30′, so as to form with them angles of 125° and 55°. The height of the prism is to the edges of the terminal faces in the ratio of 8 to 7.