Opal Brightness Explained
Opal brightness is graded on the B1–B5 scale, where B1 is very dim and B5 is vivid and intense.
Georgie's Gem Studio
Large Boulder Opal Necklace - Blue‑Green Pinfire (Natural Finish, Leather Cord)
Large Boulder Opal Necklace - Blue‑Green Pinfire (Natural Finish, Leather Cord)
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The Cerebralstone Drift - A large boulder opal with soft blue‑green pinfire resting over an intricate, brain‑like matrix pattern, its gentle lines and contours giving it a calm, thoughtful, almost cerebral presence.
This large drilled boulder opal necklace has a soft blue‑green pinfire shimmer across its polished freeform surface, giving it a calm, earthy glow.
The stone retains natural miner‑cut character, with gentle imperfections on the back that speak to its authenticity and origin.
With brightness 1, the colour play is subtle and understated - perfect for those who love opal’s organic beauty without bold flash. Its generous size and smooth, tactile finish make it a grounding, everyday statement piece.
Finished on an adjustable leather cord, it’s ready to wear straight away.
- Opal Type: Boulder Opal
- Format: Solid
- Colour: Blue, Green
- Pattern: Pinfire
- Shape: Freeform
- Finish: Polished with natural imperfections
- Brightness: B1 (of 5)
- Stone Dimensions: 40 × 24 × 4 mm
- Weight: 12 g
- Back: Minor imperfections only on reverse
- Fitting: Leather cord (adjustable)
- Source: Miner‑direct
- Origin: Boulder Opal Fields Australia
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About Our Opals
We only work with Australian opals, direct from #MinerToMaker.
Every stone is natural, untreated, and individually cut.
No two opals are ever the same - each piece is one‑of‑a‑kind.
We source directly from small Australian miners and cutters.
Every opal comes from Queensland’s ethical, regulated opal fields.
All photos are taken with a macro lens, remember to check the opal dimensions before purchasing.
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More from the Studio
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Stories from the Studio
Read our latest posts -
Ethical Opal Sourcing
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Caring for Australian Opal
A simple guide -
Opal Brightness Guide
Judging brightness