Australian Boulder Opal

Introduction

Australian boulder opal stands out as a unique gemstone, known for its striking play of color and distinctive matrix. Primarily sourced from Queensland, this opal develops within ironstone boulders, creating a captivating mix of vibrant opalescence against natural, earthy tones. The patterns and color flashes - from electric blues and greens to warm reds and yellows - ensure each piece is entirely unique.

Discover detailed properties of boulder opal in our boulder opal information guide.

Understanding Opal

Opal is best known for its play of color, a mesmerizing display of rainbow-like hues that shift with light or viewing angle. Not all opals show this feature - only those classified as precious opal do. Among precious opals, the black opal from Australia is highly valued, first found in the 1800s at Lightning Ridge in New South Wales.

Explore comprehensive details on opal gemstones through our general opal information page.

Types of Australian Opal

Australia supplies nearly all the world's opal, but 90% of its output is light-colored opal. Rare black opal makes up just 8% and is prized for its dark body tone, which enhances the vibrancy of the color play compared to common white opals.

The remaining 2% is boulder opal, the second most valued type. This form is distinctive and holds strong appeal in the gem market.

Discovery and Formation of Boulder Opal

First uncovered around 1870 in Quilpie, Western Queensland, boulder opal embeds itself in ironstone boulders. It typically appears as thin veins in these boulders, so cutters often include some of the host ironstone matrix. That's why it's sometimes called opal in matrix.

Characteristics and Cutting

What makes boulder opal particularly interesting? Well, like black opal, its dark body tone boosts the intensity of the color play. Plus, the ironstone adds density, potentially making it more durable. Due to the slender opal veins, cutting domed cabochons is often tricky. Instead, stones are shaped into free-form, irregular pieces to preserve as much opal as possible and avoid waste.

Learn essential tips for maintaining opals in our caring for opals guide.

Market Potential

Boulder opal is relatively new on the scene but shows plenty of promise. The potential mining area spans 200 to 300 kilometers in Western Queensland, and only a fraction has been explored so far - much larger than black opal fields.

Frequently Asked Questions