Emily2020 0 Posted June 13 Share Posted June 13 Hello, We were digging in the garden today and dug up this interesting looking rock. I've not come across anything like it before so tried to Google but didn't find much, so thought I'd try a forum in case anyone might have an idea! Does anyone know what this is? Thank you! P.S. I'm based in the UK. Quote Link to post Share on other sites
GeoJack 800 Posted June 13 Share Posted June 13 (edited) chalcedony? Edited June 13 by GeoJack Quote Link to post Share on other sites
Stillweaver hillbelli 234 Posted June 13 Share Posted June 13 47 minutes ago, GeoJack said: chalcedony? Or other silica mineral such as quartz Quote Link to post Share on other sites
Bedrock Bob 3,871 Posted June 13 Share Posted June 13 It is boxwork quartz. 1 Quote Link to post Share on other sites
clay 967 Posted June 13 Share Posted June 13 Minerals seldom provide enough information from a picture for a positive identification. You may have to do some testing to get to a positive ID. It's looks like Calcite or one of the Calcite group maybe Siderite? I've seen a lot of calcite that formed that way. It's often carved and sold in Mexico as "honey onyx" even though it's a carbonate and unrelated to true onyx. If you live in an area that's predominately limestone it's probably Calcite. Here's a map of the limestone regions in the UK. To test to see if it's Calcite drop a small piece in vinegar and watch for little bubbles to form. Don't leave in there too long (overnight) or you will dissolve the rock if it's Calcite. If you don't get any bubbles try to scratch it with a knife. If it scratches but doesn't bubble try scratching it with a penny. If it scratches with a penny it's likely to be Selenite (gypsum). Selenite will slowly dissolve in room temperature water and the crystals will get cloudy. 1 Quote Link to post Share on other sites
d_day 307 Posted June 13 Share Posted June 13 I think it’s most likely to be calcite. Quote Link to post Share on other sites
Bedrock Bob 3,871 Posted June 13 Share Posted June 13 The vinegar will tell the tale. Quote Link to post Share on other sites
4meter 186 Posted June 13 Share Posted June 13 A few of the larger, solitary, crystals look to have flattish tops. Calcite (boxwork) as d-day said. Quote Link to post Share on other sites
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