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Identity HelpTranslucent Rock
22nd Feb 2010 21:43 UTCGarrett Moore
While working for an importer of antique furniture from Argentina in the 1980's, I found this rock rattling around behind the drawer of a heavily carved and expensive desk.
Due to the rock's unusual translucent appearance, rather than toss it in the bin, I kept it.
Upon examining the rock, I noticed that it had many concave divots, and the overall shape of a stone axe head.
However, the rock's size, 2.5 in x 2.75 in, appearance, and feel when held in my hand has always led me to believe it was possibly a flint knapping tool.
http://inlinethumb35.webshots.com/44066/2715868160048211331S600x600Q85.jpg
The rock cannot be scratched with a stainless steel knifeblade, and it has a somewhat shinier appearance inside of the divots.
While much of the surface is covered with small bubble-like inclusions which give it a frosty appearance, there are some spots where there are no "bubbles" which appear as a more solid underlying color.
When backlit, some areas appear nearly transparent, before becoming translucent.
When wetted, the rock goes a bit darker, and the bubble-like inclusions become more apparent.
Years ago, I stopped-in to a local rock shop and the man told me it was rose quartz, however I have never seen an example of rose quartz which looked like this rock does.
After an exhaustive search of the photos here at Mindat, I have not seen anything which looks like this rock.
Some additional high-rez photos at Webshots.
Thanks ahead of time for any comments, and thanks for an awesome website!
Garrett
22nd Feb 2010 22:16 UTCCobalt
22nd Feb 2010 22:50 UTCCobalt
22nd Feb 2010 22:53 UTCMatt Neuzil Expert
23rd Feb 2010 00:29 UTCAnonymous User
23rd Feb 2010 13:49 UTCSpencer Ivan Mather
Spencer.
23rd Feb 2010 19:53 UTCDon Saathoff Expert
23rd Feb 2010 23:00 UTCGarrett Moore
I have had this rock for about 25 years, so it is very interesting to finally get some input as to what it actually is.
Haha...I have lost the rock twice, and at one point I asked my sister to put it in her aquarium so I would always know where to find it.
Ten years later I recently found my sister had placed it among some rocks my mother had collected on outings with a geology class she had taken after retiring.
OK,...there is no banding....so Quartz, va. Chalcedony, va. Carnelian?
Any explanations what caused the white inclusions?
Also, any ideas on these two spots which seem totally out of place for the rest of the surface?
The longer one on the right, seems to have a darker material inside it.
Thanks again one and all for your comments
Cheers
Garrett
http://inlinethumb44.webshots.com/46123/2995036660048211331S600x600Q85.jpg
23rd Feb 2010 23:25 UTCCobalt
24th Feb 2010 00:18 UTCDon Saathoff Expert
Garrett....chalcedony often forms in bubbles in a volcanic flow....as in a rhyolite flow....any imperfections or patterns on the inside wall of the amygdule (ex-bubble) would transfer to the silica filling.
1st Mar 2010 11:45 UTCJorge Dascal
Jorge Dascal
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Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 25, 2024 10:22:59