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ARAGONITE, one of the mineral forms of calcium carbonate (CaCOj), the other form being the more common mineral calcite. It crystallizes in the orthorhombic system, and the crystals are either prismatic or acicular in habit. Simple crystals are, however, rare; ...

... t of Albarracin is the remarkable fountain called Cella, 3700 ft. above the 3*4 ARAGONITE— ARAGUA sea, which forms the source of the Jiloca; and between this river and the Sierra Molina is an extensive lake called Gallocanta, covering about 6000 acres. The cli ...

ARGENTITE, a mineral which belongs to the galena group, and is cubic silver sulphide (AgjS). It is occasionally found as uneven cubes and octahedra, but more often as dendritic or earthy masses, with a blackish lead-grey colour and metallic lustre. The cubic c

ARGONNE, a rocky forest-clad plateau in the north-east of France, extending along the borders of Lorraine and Champagne, and forming part of the departments of Ardennes, Meuse and Marne. The Argonne stretches from S.S.E. to N.N.W., a distance of 63 m. with an

ARGYRODITE, a mineral which is of interest as being that in which the element germanium was discovered by C. Winkler in 1886. It is a silver sulpho-germanate, AgjGeSe, and crystallizes in the cubic system. The crystals have the form of the octahedron or rhombi