African opal, 2.24 carats

Technical details: Type: African Opal (Opal) Weight: 2.24 Carats Shape: Cabochon Shape Color: Black Clarity: Uncategorized (Uncategorized) Transparency: Opaque (Opaque) Hardness: 5.5-6.5 Treatment: Smoke Treated Origin: African Certification: Electronic certificate (PDF) from Saudi Laboratory (MT) - Website (www.mtgl.com.sa) Opal is a semi-precious (non-crystalline) mineral of Hydrated Silica, known for its great diversity in appearance. The most famous type is Precious Opal, which features a unique optical phenomenon called play-of-color, where iridescent flashes of different spectral colors change with the viewing angle, resulting from light interference with microscopic silica spheres arranged in a lattice. Common Opal, on the other hand, does not exhibit this phenomenon but comes in a variety of colors. Opal forms in cavities within sedimentary and volcanic rocks when silica-rich water solutions are deposited.