Australian Boulder Opal Cabochon 20ct – 23x15x7mm

Rare Australian Boulder Opal — 20 Carats of Pure Colour

This generous 20 carat Australian Boulder Opal cabochon is a striking natural gemstone with the vivid, shifting play-of-colour that makes boulder opal one of the world's most coveted gems. Measuring 23 x 15 x 7mm, it offers excellent surface area to display its spectral colour flashes — a true collector's stone.

Specifications

• Type: Boulder Opal cabochon — natural Australian opal in ironstone host rock
• Weight: 20 carats
• Dimensions: 23mm (length) x 15mm (width) x 7mm (depth)
• Cut: Cabochon — smooth, domed, and polished to maximise play-of-colour
• Origin: Queensland, Australia
• Backing: Natural ironstone matrix retained — adds structural strength and a beautiful natural contrast

Play-of-Colour

Boulder Opal's extraordinary play-of-colour produces flashes of electric blue, green, gold, red, and violet that shift and dance as the stone moves in light. Every boulder opal is entirely unique — no two stones share the same colour pattern or intensity.

About Boulder Opal

Found almost exclusively in Queensland, Australia, boulder opal forms in thin seams within ironstone boulders. The ironstone host rock is retained as part of the finished stone, providing durability and a striking natural backdrop for the opal's colour. Australia produces over 95% of the world's precious opal supply.

Ideal For

A superb choice for collectors, lapidary enthusiasts, or jewellers seeking a substantial stone for a bespoke pendant, ring, or brooch. At 20 carats, this cabochon has impressive presence and weight.

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.