Australian Opals 

Formation and Mining

At Shaun's Opals, we pride ourselves on providing some of the finest Australian opals. These gems are primarily found in the sedimentary rocks of South Australia, New South Wales, and Queensland. The formation process involved silica-rich water seeping into cracks and cavities in the rock, then solidifying over millions of years. For opals to form, specific geological conditions are required: 

1. Silica Source: Silica-rich solutions from weathering of surrounding rocks.

2. Water: Water to transport silica and fill cracks and voids.

3. Stability: Stable conditions to allow the slow deposition of silica over time.

4. Void Spaces: Cavities and cracks in the rocks where the opal can form. 

5. Time: Millions of years for the opal to mature and stabilise.

Types of Australian Opals

Black Opal: The rarest and most valuable, primarily found in Lightning Ridge.

White Opal: Common and found in South Australia.

Boulder Opal: Found in Queensland, with the opal layer attached to ironstone.

Crystal Opal: Transparent to semi-transparent with vibrant colours.

Why Are Australian Opals So Rare?

Australian opals are rare due to the specific geological conditions required for their formation. Black opals, in particular, are exceptionally rare and highly sought after. At Shaun's Opals, we take great care in sourcing these rare gems to bring you the best selection possible.

Opal Stability

Australian opals are known for their stability and durability, making them less prone to cracking compared to some other opals. We ensure that every opal at Shaun's Opals meets our high standards for quality and longevity.

Opal Color and Patterns

Australian opals are celebrated for their intense and diverse play-of-colour. Patterns like harlequin, pinfire, and rolling flash add to their visual appeal and value. We select only the most visually stunning opals for our collection at Shaun's Opals.

Water Content in Opals

Australian opals generally have lower water content, contributing to their stability and resistance to cracking. This makes them a durable and lasting choice, and at Shaun's Opals, we provide information on how to maintain their beauty.

Rarity and Value

The rarity of certain types, especially black opals, combined with their brilliant colours and patterns, makes Australian opals some of the most valuable in the world. The highest quality opals can command very high prices due to their vivid colours, unique patterns, and overall beauty. At Shaun's Opals, we are committed to offering you opals that are not only rare but also exceptional in quality.

Categories that Define Opals

Play-of-Colour: The play-of-colour is the primary factor in determining an opal's beauty and value. It occurs due to the diffraction of light caused by the microscopic structure of silica spheres within the opal.

Body Tone: The body tone of an opal ranges from N1 (jet black) to N9 (white). Black opals (N1 to N4) are the most valued due to their dark background, which makes the play-of-color stand out more vividly.

Transparency: Ranges from opaque to transparent. Crystal opals (transparent to semi-transparent) are particularly prized for their clarity and the brilliance of their colours.

Pattern: Patterns are a critical aspect of an opal’s appearance and value. Common patterns include:

 Harlequin: A rare pattern with a mosaic of broad, angular patches of colour.

  Pin-fire: Small, pinpoint-like flashes of colour.

  Rolling Flash: Large areas of colour that appear to move or flash as the stone is turned.

  Chinese Writing: Unique, intricate lines resembling Chinese characters.

  Ribbon: Parallel bands of colour.

Brightness: Refers to the intensity of the play-of-colour. Brighter opals are more valuable.

  Scale: B1 (brilliant) to B7 (dull).

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