Tamara Posted April 7, 2016 Share Posted April 7, 2016 I found this on a beach in the Florida Keys some years back after Hurricane Georges scoured the keys for a straight 24 hours. It is 5" X 4" at it's widest points. I have not found anything like it on the internet. It appears to be solid crystal. Can anyone identify the species and possibly tell me it's approximate age? Thanks! Link to comment Share on other sites More sharing options...
Ludwigia Posted April 7, 2016 Share Posted April 7, 2016 I may be wrong, but I don't see any tell-tale structures that suggest coral, but see rather a pure crystal aggregate. Maybe calcite. Does it fizz when you put a few drops of vinegar on it? Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Tamara Posted April 7, 2016 Author Share Posted April 7, 2016 Hi Ludwiga, I just put vinegar on it an no fizz. I am new to this. What does that mean? Link to comment Share on other sites More sharing options...
Ludwigia Posted April 7, 2016 Share Posted April 7, 2016 (edited) It means it may be quarz or another mineral which is impervious to weak acids. Can you scratch it with glass? Edited April 7, 2016 by Ludwigia Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
howard_l Posted April 7, 2016 Share Posted April 7, 2016 See if it scratches glass, if it does it may be quartz Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Tamara Posted April 7, 2016 Author Share Posted April 7, 2016 It does not scratch glass it's smooth and roundish it just slides. I added another view so you can see the base a little more. Link to comment Share on other sites More sharing options...
Ludwigia Posted April 7, 2016 Share Posted April 7, 2016 See if it scratches glass, if it does it may be quartz oops! That's what I meant to say. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Ludwigia Posted April 7, 2016 Share Posted April 7, 2016 Now I'm wondering if it might be gypsum. Does it feel smooth and soapy? Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
howard_l Posted April 7, 2016 Share Posted April 7, 2016 See if a penny scratches it easily, also try heating up the vinegar a little and see if the rock fizzes then. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Tamara Posted April 8, 2016 Author Share Posted April 8, 2016 It does not feel soapy, it is rough. A penny does not scratch it easily. If I use force and scratch back and forth I can get some small flakes off of it but no scratch seen. It came from the ocean what could it be besides coral? I seems to be very hard and dense but translucent and sparkly. There are worm holes on bottom side. I will try heated vinegar. Link to comment Share on other sites More sharing options...
Ludwigia Posted April 8, 2016 Share Posted April 8, 2016 Like I already said, my impression is that it's not a coral or any other formerly living being for that matter, but maybe howard sees that otherwise... Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
howard_l Posted April 8, 2016 Share Posted April 8, 2016 Another possability that it could be Barite. Barite can form in very small massive crystals, with a hardness of 3 to 3.5, so a penny may not scratch it. It may have at one time been coral but if it was it has been recrystallized to the point there is no way to no for sure. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Guguita2104 Posted April 8, 2016 Share Posted April 8, 2016 (edited) I also don't see any coral structure (coralites or septa, etc). Regards, P.S-It continues to be a cool geological structure. Edited April 8, 2016 by Guguita2104 Link to comment Share on other sites More sharing options...
Adber Posted April 10, 2016 Share Posted April 10, 2016 Looks like calcite to me, Calcite does not necessarily fizz with vinegar. This specimen being from Florida eliminates pretty much anything but calcite and quartz. If you placed muriatic acid (for cleaning pools) it will fizz. The hardness is correct for calcite, and the crystal structures look similar to ones I found. As for the age, calcite is young, and in this environment forms after the actual rock formation. Link to comment Share on other sites More sharing options...
howard_l Posted April 10, 2016 Share Posted April 10, 2016 Calcite is young??? You can guess that because it came from Florida, it is more than likely Cenozoic but you can not deturmine age from a mineral. Calcite can be found from PreCambrian to Recent. In a lot of cases Aragonite forms first and is later replaced by calcite. Howard_L http://triloman.wix.com/kentucky-fossils Link to comment Share on other sites More sharing options...
Ludwigia Posted April 10, 2016 Share Posted April 10, 2016 Looks like calcite to me, Calcite does not necessarily fizz with vinegar. This specimen being from Florida eliminates pretty much anything but calcite and quartz. If you placed muriatic acid (for cleaning pools) it will fizz. The hardness is correct for calcite, and the crystal structures look similar to ones I found. As for the age, calcite is young, and in this environment forms after the actual rock formation. I'd go with this guy, since he seems to be in the know. Thanks for the info. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
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