Mineral variety Healing crystal

Boulder Opal

✦ Stone of the Outback ✦

Crystal lore: 🌳 Grounding 🎨 Creativity 🔥 Confidence

Variety of Opal.

Boulder Opal specimen — Veins of opal in a boulder opal.jpg · Wikimedia Commons (see file page for author & license)

📜 Key facts

Age	Cretaceous host rocks
Origin & sources	Western Queensland, Australia (Winton, Quilpie and Yowah).
Composition	Precious opal in seams within ironstone boulders, usually cut with the brown ironstone backing left on. Opal is hydrated amorphous silica (SiO₂·nH₂O), Mohs 5.5–6.5.

How it forms

Silica-rich water seeped into cracks, cavities and fossils, then slowly evaporated. Tiny silica spheres settled out. In precious opal they are stacked in a neat, regular grid that diffracts light into play-of-colour. In common opal they are jumbled.

Mineral data: see Opal.

🌍 Where it's found

Type locality
Notable source / deposit
Country of origin

Marker positions are approximate (region or locality level). Type localities from Wikidata; notable sources curated by Crystopedia.

✨ Metaphysical & Folklore

These are traditional and folk beliefs from crystal lore. They are not scientific or medical claims – crystals are not a substitute for professional care.

Opal veins in ironstone are linked in lore to grounding, strength and steady creativity.