CONCHOIDA.L CORNEOUS SILVER-ORE. 61 pearl-grey, and greenish-white, which passes into pale olive-green. It occurs massive. The lustre is splendent and adamantine. The fracture is sometimes flat and large conchoidal, sometimes small and imperfect conchoidal. The fragments are indeterminate angular, and rather sharp-edged. It occurs in large and small granular distinct concre tions. It is generally semi-transparent, but sometimes passes into transparent. The streak is resinous, and with a lower lustre than the fracture. It is very soft. It is malleable. Specific gravity, 4.7488. Constituent Parts. Silver, - Oxygen, - - - Muriatic Acid, - - 16-4 100.0 Klaproth, Beit, b iv. s. 12. This is the purest and richest subspecies of corneous silver-ore. Geognostic and Geographic Situations. This mineral occurs in compact limestone, along with common corneous silver-ore, and has hitherto been found only at Guantahoyio (Huantajayo) in Peiu. Observations.