Quartz-rich sandstone pebble with a natural perforation ("hag stone") — sedimentary Identification & Properties | Geo-Gem
Quartz-rich sandstone pebble with a natural perforation ("hag stone") is a sedimentary. 1) Hand lens: look for distinct rounded sand grains—confirms sandstone. 2) Scratch test: try a steel nail and then try to scratch a piece of glass; quartz-rich sandstone should scratch glass. 3) Acid test: place a drop of 10% HCl (or stron…
Explore Geo-Gem
- AI Rock & Mineral Identification — snap a photo and get an instant AI-powered ID
- Community Discoveries — browse finds from rockhounds around the world
- Field Guide — regional guides to rocks, minerals, and geology
- Rock & Mineral Database — comprehensive identification reference
- Marketplace — buy and sell specimens with verified collectors
- Rockhound Groups — join local clubs and online communities
- Events & Field Trips — upcoming geology events near you
- Leaderboard — top contributors in the community