Precious opal is a captivating gemstone, one of the world's most valuable and unique minerals. Its main feature is a phenomenal play of color, known as opalescence or iridescence. This effect occurs due to the diffraction of light on microscopic silica spheres within the stone, creating dynamic flashes and shifts of all rainbow colors — from vibrant blues and greens to fiery reds and oranges, changing with viewing angle and lighting. As hydrated amorphous silicon dioxide, each precious opal is an unparalleled work of nature.
The most renowned and richest deposits are found in Australia (famous for its black and white opals), as well as Ethiopia (known for vibrant 'Welo' opals), Mexico (fire opals), Brazil, and the USA. Thanks to its exceptional beauty and the relative rarity of quality specimens, precious opal is highly prized in jewelry and among collectors. Its unique play of light and color makes each stone distinct, symbolizing ever-changing beauty. Historically, opals have been associated with inspiration, and their bright, dynamic nature has been valued for its uniqueness.
Precious opal is an ideal choice for connoisseurs of rare and unusual gemstones, for those seeking an exceptional piece of jewelry, or looking to add a true marvel of nature to their collection.
Physical properties
Chemical formula
SiO₂·nH₂O (Hydrated Silicon Dioxide)
Hardness
5.5 - 6.5 on the Mohs scale
Crystal system
Amorphous (lacks crystalline structure)
Transparency
Transparent to opaque
Luster
Vitreous to resinous
Color
Displays play of color (opalescence) across the entire spectrum (blue, green, red, orange, yellow, violet) against a body color (white, black, gray, colorless, yellow, orange, red)
Specific gravity
1.98 - 2.25
Varieties
Jewelry with this mineral
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