Emily2020 Posted June 13, 2020 Share Posted June 13, 2020 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 comment Share on other sites More sharing options...
GeoJack Posted June 13, 2020 Share Posted June 13, 2020 (edited) chalcedony? Edited June 13, 2020 by GeoJack Quote Link to comment Share on other sites More sharing options...
Guest Posted June 13, 2020 Share Posted June 13, 2020 47 minutes ago, GeoJack said: chalcedony? Or other silica mineral such as quartz Quote Link to comment Share on other sites More sharing options...
Bedrock Bob Posted June 13, 2020 Share Posted June 13, 2020 It is boxwork quartz. 1 Quote Link to comment Share on other sites More sharing options...
clay Posted June 13, 2020 Share Posted June 13, 2020 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 comment Share on other sites More sharing options...
d_day Posted June 13, 2020 Share Posted June 13, 2020 I think it’s most likely to be calcite. Quote Link to comment Share on other sites More sharing options...
Bedrock Bob Posted June 13, 2020 Share Posted June 13, 2020 The vinegar will tell the tale. Quote Link to comment Share on other sites More sharing options...
4meter Posted June 13, 2020 Share Posted June 13, 2020 A few of the larger, solitary, crystals look to have flattish tops. Calcite (boxwork) as d-day said. Quote Link to comment Share on other sites More sharing options...
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