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< CONCIIOIDAL PHOSPHATE OF LEAD. *403 1. Perfect six-sided prism, generally bulging, and al most globular. 2. The same figure, with straight planes, flatly acu minated on the extremities, with six rather con vex planes; the acuminating planes set on the la teral planes. 3. Double six-sided pyramid; the lateral planes of ten convex, and the planes of the one pyramid resting on those of the other. The edge of thfe common base, and the summits of the pyramids, sometimes truncated. The crystals are sometimes single, sometimes aggrega ted, in the rose, bud, or globular form. Internally, the lustre is shining and resinous. The fracture is conchoidal. It is translucent. The streak is yellowish-white. It is soft, inclining to semihard. It is brittle. Specific gravity 7.261 ; Karsten. Constituent Parts. Oxide of Lead, Phosphoric Acid Arsenic Acid, Muriatic Acid, Water, 76.8 9.0 4.0 7.0 1.5 77.5 7.5 12.5 1.5 98.3 J.augier, Ann. d. Mus. t. vi. p. 171. Pose, Journ. d. Chem. & Phys, t. ii. 220. Geognostic