Sphalerite

Field of view: 20 mm. A sphalerite crystal associated with siderite. The dark brown crystal at the center is a part of tetrahedron of sphalerite. The transparent prisms under sphalerite are quartz crystals. The reddish-brown rhombohedrons around spalerite are siderite. The black host with a vitreous luster is sulfide-rich quartz.

Recovered from a quartz vein in a moderate-temperature hydrothermal deposit associated with rhyolite. Formed in the early Miocene (21 Ma).

Sphalerite from this location was described in 1917.

Field of view: 40 mm. Granular sphalerite. The yellowish-brown grains are sphalerite. The surrounding white parts are gangue quartz. The earthy opaque white parts are clay filling open spaces of quartz.