Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
Rock Type: mineral

Physical Properties
Mohs hardness: 5.5-6.0; Color: Pale pink to salmon, often with white or gray mottling; Luster: Vitreous to sub-vitreous; Crystal system: Amorphous (non-crystalline); Specific Gravity: 1.9-2.3.
Formation & Geological History
Formed by the precipitation of silica from groundwater at low temperatures, typically in volcanic ash beds or sedimentary environments. Most pink opal comes from the Tertiary period.
Uses & Applications
Primarily used in the jewelry industry for beads, cabochons, and carvings. It is also highly popular in the metaphysical and gemstone collecting markets.
Geological Facts
Unlike precious opal, pink opal does not show a 'play of color' (opalescence). Its pink color is often caused by inclusions of organic compounds called quinones or tiny traces of manganese palygorskite.
Field Identification & Locations
Identify by its characteristic waxy or milky appearance and lack of fire. It is commonly found in the Andes Mountains of Peru. For collectors, look for uniform pink saturation without excessive gray or brown host rock.
Identified on: 5/3/2026
Mode: Standard