3°° Siliceous Genus. Its tranfitions are into opal, flint, quartz, jaf- P er j cryfoprafium, and felfpar. zd Family. Carnelian. Its colours are of various lhades of red, frotn the deep blood red, to the lighter, almoft white, or reddifli brown, or honey or Aax yellow, or yel- lowifh brown, and often thefe colours or fhades occur in the fame mals, cither in gradation, or ltripes, or fpots. Amorphous, or in blunt or fomewhat rounded malles, with rough or unevcn furfaces, or flalac- t'itic. Its Iuflre fcarcely i. Tranfparency 3.2.1, of fen cloudy. 5 Its fra&ure, conchoidal. Fragments, 3. Hardnefs, 10. Sp. gr. from 2,597 to 2,63. It is infufible, but loi'es its colour at 16o°, nor even by pure air is it melted as perfeftly as calce- dony is, nor in a chalk crucible in thofe parts that touch the chalk as calcedony is. 2 Gerh. Gefch. 10. But by the ufual fluxes it is affe&ed nearly as common calcedony. Some confider it as a compound of jafper and calcedonian. Some are found partly withered by expofure to the air, particularly the ftala&itic, It fometimes graduates into quartz. 30th Spccies.