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Species 3.—Cryſtal.
Specific Character,
An hexangular Column of ſix equal Sides, of the ſame Tickneſs from End to End; and terminated each way by an hexangular Pyramid; colourleſs, pellucid.
Varteties.
1. In Shape.
a By Accident in their Concretion.
Perfect,
1.—Cloſe Cryſtal,
A Cryſtal of 18 Planes in a ſhort Column, and two long Pyramids.
Wanting the intermediate Column,
1b.—Gibbous Cryſtal.
2.—Bellyed Cryſtal,
of 12 Planes, in two hexangular Pyramids, baſe to baſe.
3.—Edgy Cryſtal,
of 16 Planes, in two octangular Pyramids, baſe to baſe.
Wanting the lower Pyramid,
4.—Spiry Cryſtal,
of 12 Planes in a hexangular Pyramid, on an hexangular Column:
5.—Broad Cryſtal,
of 10 Planes in a pentangular Column, and pentangular Pyramid.
6.—Planed Cryſtal,
of 20 Planes in decangular Columns, and decangular Pyramid.
7.—Oblique
