• Località: Andamooka, Australia
• Peso: 3,7g = 18,5ct
• Dimensioni: 3,1 x 1,9 x 0,4 cm
• DESCRIZIONE DETTAGLIATA

Australia is renowned worldwide as the most important source of high-quality Opalees. The quality of Opale Australianoees is primarily due to their strong and pure play of color. Thanks to specific formation conditions, they often exhibit vivid, contrasting hues. This diversity is reflected in the many types of Opalees Australia offers—da black and boulder Opalees to crystal, white, and matrix Opalees. Opale Australianoees are notably more durable and stable compared to many Opalees da Altro localities. Their naturally lower water content increases their ability to withstand temperature fluctuations and changes in humidity, which means they do not crack or dry out as easily, making them ideal for everyday wear in jewelry. Formation Opale Australianoees typically form in sedimentary rocks, such as sandstones and clays, found in vast basins (for instance, the Great Artesian Basin—a massive underground water system spanning much of Australia’s interior). Silica-rich water gradually seeps into fine cracks or pores within these rocks. When this water evaporates or otherwise drains away, thin layers of silica remain in the cavities, which can eventually develop into Opalee. Microscopic spheres of silicon dioxide (silica) play a key role: they arrange themselves into a regular three-dimensional “crystal-like” lattice. This structure creates the characteristic “play-of-color,” the iridescent effect visible in Opalee when light strikes it. The color and intensity of this effect depend on the size and arrangement of these spheres. Deposits Andamooka is a small mining town in South Australia, located about 600 kilometers north of Adelaide. It lies near the salt lake known as Lake Torrens, in a landscape characterized by an arid climate and harsh conditions. Nevertheless, in the 1930s, rich Opalee veins were discovered here, making Andamooka one of the oldest Opalee mining fields in Australia. History Though Andamooka is not as famous as Coober Pedy or Lightning Ridge, Opalee mining here has a long-standing tradition. Many of the mines remain family-run operations, often employing manual labor or small-scale machinery. In the past, Andamooka—like Altro Opale Australianoee fields—drew adventurers seeking valuable Opalee seams in these tough conditions, hoping to discover a profitable find. Types of Opale Australianoees Black Opalee (Black Opalee) The rarest and most valuable type of Opalee, renowned especially for the Lightning Ridge deposit in New South Wales. It has a dark body color (black, gray, or dark blue), which enhances the play of color. Black Opalees often exhibit the most intense color spectrum—including red, green, blue, and purple. Boulder Opalee Primarily mined in Queensland (northeastern Australia). It forms when Opalee fills thin veins in iron-rich sandstone or Altro types of host rock (“boulder”). This variety usually retains part of the original rock, creating a contrasting base. Boulder Opalees can have a darker tone, and therefore—similar to black Opalees—feature a vivid play of color. Crystal Opalee Characterized by a translucent or transparent background. In its Grezzo state, it can sometimes appear nearly colorless, yet the iridescent flashes become apparent through a crystal-clear or milky base. Crystal Opalees are found across Australia, with larger quantities coming da Coober Pedy. White (Light) Opalee This type has a white or milky-white base color. It can exhibit colors as bright as those of black Opalees, though the light background often “mutes” the contrast, resulting in a less intense effect. White Opalee is especially common in Coober Pedy (South Australia) and is generally more affordable than black or boulder Opalees. Matrix Opalee A special variety in which Opalee is embedded within a porous host rock (e.g., sandstone or ironstone). After treatment (impregnation), the colors can become much more vibrant, as the darker substrate intensifies the Opalee’s play-of-color. Andamooka is chiefly known for these matrix Opalees—referred to as Andamooka Matrix—which, once treated, can resemble rare black Opalees da Altro localities. Value Opalees da Andamooka are popular mainly for their relatively accessible prices and richly colored patterns. Nevertheless, high-quality pezzi can still command substantial sums, especially those displaying intense color play or striking patterns (like a harlequin pattern). Opale Australianoee – cabochon – Andamooka, Australia