Orpiment

Field of view: 3 mm. Orpiment associated with realgar. The radial groups of tabular yellow crystals with a resinous luster are orpiment. The surrounding white parts are gangue quartz. The red grains at the upper right are realgar.

Recovered from an open space of a quartz vein in a low-temperature hydrothermal deposit formed by a andesite dike in andesitic tuff breccia filling a caldera. Formed in the late Miocene (6 Ma).

Orpiment from this location was described in 1927.