Pink Opal — The Andean Common Opal
Pink Opal — The Andean Common Opal
Translucent to opaque pink common opal from Peru, coloured by organic compounds and trace manganese
Pink opal is a translucent to opaque variety of common opal coloured pink to peach by a combination of trace manganese, iron compounds, and organic palygorskite-type pigments, principally from deposits in the Peruvian Andes. The variety is also marketed as Andean opal, and is distinguished from precious opal by its lack of play-of-colour: pink opal is valued for its smooth, milky-pink body colour rather than for diffraction phenomena. The stone has been worked since pre-Columbian times in Peruvian and Bolivian metalwork and remains an established mid-tier component of the contemporary coloured-stone trade.
Composition and origin
Like all opal, pink opal is hydrated amorphous silica, SiO2·nH2O, with water content typically 6 to 10 percent by weight. Common opal differs from precious opal in lacking the ordered packing of uniform silica spheres responsible for play-of-colour; the silica in common opal is disordered or contains spheres of inconsistent size, so light is scattered without coherent diffraction. The pink colour arises from a combination of trace manganese and iron and from organic pigments associated with palygorskite, a fibrous magnesium-aluminium silicate that occurs as inclusions in much Peruvian pink opal.
Peruvian pink opal forms in volcanic rhyolite host rocks of the Andes mountains, principally in the Acari district of the Arequipa region south of Lima. The stones occur as nodules and seams within the rhyolite, weathered and concentrated in soil horizons accessible by surface and shallow underground mining. Lesser quantities are produced from deposits in Mexico and the United States, and a soft-pink common opal has been documented from Australian, Indonesian, and Tanzanian sources.
Quality and grading
Quality variables in pink opal include colour saturation (saturated salmon-pink commands a premium over pale pink and chalky white-pink material), uniformity (even body colour without dark streaks or matrix inclusions is preferred), translucency (semi-translucent stones with visible internal glow rate higher than fully opaque material), and surface polish (the soft hardness makes high polish challenging but achievable on quality material).
Hardness is 5.5 to 6.5 on the Mohs scale, comparable to other opal varieties, and the same care recommendations apply. Pink opal is typically cut as cabochon, with carved and bead applications also common. Faceted pink opal is rare and most often encountered in transparent crystal-grade material from secondary sources.
Care
Pink opal shares the structural water content of all opal varieties and the associated vulnerability to thermal shock, dehydration, and mechanical impact. Care recommendations are conservative: avoid prolonged dry storage, avoid ultrasonic and steam cleaners, avoid temperature extremes, and prefer bezel or protected mounts for ring designs. Long-term ultraviolet exposure has been observed to fade the colour of some pink opal specimens, with the organic-pigment component being the more vulnerable contributor.
In the trade
Pink opal occupies a mid-tier position in the contemporary coloured-stone market, with prices typically in the range of a few dollars to a few tens of dollars per carat for standard quality and reaching higher figures for top-saturation specimens with strong translucency. The stone is widely used in fashion jewellery, particularly in pendants, earrings, and statement pieces where its smooth pastel colour reads strongly under daylight. Carved pink opal is a recurring component of contemporary art-jewellery design.
The stone's accessibility, soft pink palette, and Andean origin story have given it a distinct market identity separate from the precious-opal trade. Buyers should ensure that disclosure follows the convention of identifying the material as common opal or pink opal rather than as opal alone, since the term opal without qualifier carries an implication of play-of-colour that pink opal does not display.