Realgar Quartz specimen with some Orpiment, just a stunning little display of colours and formations.
Palomo Mine, Andes, Peru.
8.2cm x 5.3cm x 2.3cm, 75g.
As4S4 Arsenic Sulfide.
Warning Poisonous, contains Arsenic – no healing properties for this one 😉
A major ore of arsenic, formerly used for pigments, firework colouring agent and as mineral specimens.
Realgar is an oddball among the sulfides. It is one of only a few sulfides that are not metallic or opaque or blandly coloured. The structure is analogous to that of sulphur and resembles sulphur in most respects except for colour (the name “ruby sulphur” has been applied to Realgar). Sulphur has a structure composed of 8 Sulphur atoms linked in a ring. Realgar’s structure alternates between Sulphur atoms and arsenic atoms producing rings of As4S4. The Arsenic atoms affect the structure altering it from Sulphur’s orthorhombic symmetry to Realgar’s monoclinic symmetry.
Realgar occurs in hydrothermal veins with valuable metal Sulphide ores and its bright red colour can be an aid to prospectors. It also can be found in hot spring deposits and as a volcanic sublimate product (crystallizing from vapors). Realgar gets its name from the Arabic words for “powder of the mine” (rahj al ghar). Realgar is famous for some wonderfully beautiful specimens. Some specimens can have a deep ruby red colour with an amazing clarity and a high luster. The color of Realgar is truly something to appreciate and cherish.