gemstone

Rough orange opal

Opal, hydrated amorphous silica (SiO₂·nH₂O)

AI-generated identification · may be incorrect

Small, translucent to opaque orange-yellow piece with a vitreous-to-waxy luster and irregular fracture; opal is amorphous (no crystal structure) and typically Mohs hardness 5.5–6.5. The image does not show enough detail to confirm whether it is precious opal or common opal.

Identified October 13, 2026More gemstone →

Explore Rough orange opal in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms as silica-rich water deposits silica in cavities and fractures, often in volcanic rocks or sedimentary formations. Opal deposits span a wide range of geological ages.

Uses & applications

Used as a gemstone, ornamental material, and collector specimen; common opal is also collected for its color and patterns.

Geological facts

Opal contains variable water, which can affect stability and may cause cracking if it dries or undergoes sudden temperature changes.

Field identification & locations

Look for translucent areas, irregular fracture, and—if precious opal—distinct shifting play-of-color; orange color alone does not establish the variety. Major sources include Australia, Ethiopia, Mexico, and the western United States.