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EARTHY SUBSTANCES.

Crystallized Phosphate of Lime .

Apatite: so called in consequence of the errors mi-neralogists -were led into respecting its real na-ture, from its resemblance to the Emerald , Chry-solite, Hyacinth, and other gems.

•Spargel-stein, or Asparagus-stone; from the parti-cular shade of green of some of its varieties.

In hardness inferior to Fluor Spar.

Some of its varieties are phosphorescent, whenthrown in powder on burning coals.

Specific gravity 3,2.

Primitive form, a regular hexhedral prism.

Lime . ... 55 .. . 54,28Phosphoric Acid. 45 . . . 45,72

100 Klapr. 100,00 Vaaq.

Crystallized phosphate of lime is met with in thetin mines of Saxony , Bohemia, and Cornwall . Theprimitive form occurs very rarely. The prism is fre-quently so compressed as to become tabular; andits sides are generally longitudinally striated.

Crystallized phosphate of lime may be distin-guished from those precious stones with which it islikely to be confounded, by its phosphorescence andinferior degree of hardness.