How to Spot a Quality Opal: A Beginner’s Guide

At Iona Opal Australia, we believe every opal should be as unique and brilliant as the person wearing it. But how do you know you’re getting a high-quality stone? Whether you're new to opals or looking to expand your collection, understanding the basics of opal quality is key to making a confident purchase.

1. Colour Play and Pattern

The most defining feature of any opal is its play-of-colour—the flashes of red, green, blue, and gold that shimmer as the stone moves. In high-quality opals, these colours are bright, varied, and visible from multiple angles.
Top tip for black opal buyers: Red is generally considered the most valuable flash, followed by orange, then green and blue.

Patterns such as harlequin, ribbon, and pinfire are also prized. While rare patterns increase value, even common ones can be stunning when paired with bright colour play.

2. Body Tone and Transparency

Australian opals are classified by body tone—from the dark, dramatic black opals of Lightning Ridge to the soft, milky white opals of Coober Pedy. Darker stones typically offer stronger colour contrast and are often more valuable.

Crystal opals, which are transparent or semi-transparent, are also prized for their luminous depth. Cloudy or overly dull stones should be priced accordingly.

3. Cut and Shape

Quality opals are cut to enhance their natural beauty, not force them into a shape. At Iona Opal Australia, we favour freeform shapes that highlight each stone’s unique character, though calibrated cuts are available by request.

A well-cut opal with a vibrant colour play should have a smooth, symmetrical surface and display its colour evenly when viewed face-up. 

4. Solid vs Assembled Stones

Always check if your opal is solid or a composite. Doublets and triplets contain thin layers of opal glued to backing or topped with clear caps. These are more affordable but less durable and generally less valuable.

We sell only solid Australian opals—fully natural and cut from a single piece of rough. It’s the most reliable way to invest in a stone with long-term value and beauty.

When you shop with Iona Opal Australia, you’re not just buying a gem—you’re gaining a piece of our country’s rich geological story.

Explore our current collection or design a custom piece at Iona Opal Australia and discover the difference genuine quality makes.