Common opal (orange/yellow)
gem · common
Quick facts
- Formula
- SiO2·nH2O
- Hardness
- 5.5–6.5
- Luster
- vitreous to resinous
- Colors
- nearly any; here, yellow to orange without play-of-color
Common opal is hydrous silica lacking the ordered structure of crystalline quartz and may or may not display play-of-color. Orange to yellow bodycolor is widespread in Mexico, Peru, and Australia.
Uniform bodycolor, glassy to resinous luster, low heft, no banding, and conchoidal chips; absence of spectral play-of-color keeps it as common opal.
Scan yours
Photograph your specimen on arockid.com or in RockSnap / RockID. Three free IDs a day — no card.
Try a live scanComing soon on theApp StoreDownload RockSnap on the App Store — coming soonComing soon onGoogle PlayGet it on Google Play — coming soon
On the App Store, search RockSnap. Links go live when Apple and Google approve the listing. Use the web app today — same account.