Australian Boulder Opal Cabochon 16.3ct – 23x16x8mm

A Gemstone Unlike Any Other

This exceptional Australian Boulder Opal cabochon is a showcase of nature's most spectacular colour play. At 16.3 carats and measuring 23 x 16 x 8mm, it is a substantial, display-worthy stone with the vivid spectral flashes of colour that make boulder opal the most prized variety of Australian opal.

Specifications

• Type: Boulder Opal cabochon — natural Australian opal in ironstone host rock
• Weight: 16.3 carats
• Dimensions: 23mm (length) x 16mm (width) x 8mm (depth)
• Cut: Cabochon — smooth, domed, and polished to maximise play-of-colour
• Origin: Queensland, Australia
• Backing: Natural ironstone matrix retained — adds depth, durability, and a striking natural contrast

Play-of-Colour

Boulder Opal's defining characteristic is its play-of-colour — the phenomenon where spectral flashes of electric blue, green, gold, red, and violet dance across the stone's surface as it moves in light. No two boulder opals display the same colours or patterns, making this cabochon a genuinely one-of-a-kind gemstone.

About Boulder Opal

Found almost exclusively in Queensland, Australia, boulder opal forms in thin seams within ironstone boulders. The host rock is left intact as part of the finished stone, providing structural strength and a beautiful natural contrast to the opal's colour. Australia produces over 95% of the world's precious opal, and boulder opal is among its rarest and most distinctive varieties.

Ideal For

This cabochon is perfect for collectors, lapidary enthusiasts, or jewellers looking to create a bespoke, one-of-a-kind piece. Its generous size and depth make it suitable for a statement ring, pendant, or brooch setting.

Care Instructions

Opal contains water and can crack if exposed to extreme temperature changes or prolonged dryness. Store in a padded box away from direct sunlight. Clean gently with a soft, damp cloth. Avoid ultrasonic cleaners, steam, and harsh chemicals.