Gems Notes and Extracts Augusto Castellani, Mrs. John Brogden 1871

36 GEMS.times red, gray, or yellow. It is sometimes transparent,and sometimes opaque. It resembles the beryland emerald; its specific weightis from 3 to 3'235.In some specimens, especially in the white variety, abluish opal tint is observed in the direction of thevertical axis.It is fragile. Some are phosphorescent in heat,others become electrical by friction. This substancedoes not melt under the action of the blow-pipe, exceptingat its extreme edge. It dissolves slowly innitric acid, without effervescence. On account of thephosphoric acid which it contains when solid, it is veryuseful as a manure.Apatite is generally found in primitive rocks, traversinggranite, serpent marble, and in the rocks ofthe spent volcanoes in Saxony, England, Switzerland,Norway, and many American countries, where there isa great trade in it as a material for enriching land.Asparagine, which is a yellowish, translucent varietyof apatite, is found in Estremadura.AEGIPJTE.ARGIRITE is a stone only known in modern times bythe description given of itby the ancients, who alsonamed it argirodama and magnes, and it appears that insomewhat more recent times it was called argentina.Caire tells us, on the testimony of Theophrastus, that