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[tropicstones]

Hello,

I can't seem to find the answer to this question anywhere. Does schorl tourmaline degrade/waste away in tropical weather? Is it weathering resistant?

Thanks!

[Tobi]

Well, if stored directly in tropical weather, it may degrade ;) But if you keep it inside, in a display or so, the weather outside should not matter that much ...

[alfredo]

Schorl is a chemically very resistant mineral, but under tropical weathering conditions (lateritization) lots of even very resistant minerals will be destroyed, even muscovite, garnet, quartz... I've not seen any such studies specifically on schorl, but it shouldn't be surprising if it was attacked.

I once visited a weathered mica schist in the lowlands of Bolivia, where the muscovite was decomposing and big garnets were completely decomposed, but staurolite crystals were completely unaffected and still conserved their original shiny luster! Strange how micro-organisms and organic acids have such different reaction on chemically similar minerals like almandine and staurolite.

[Josele]

I think schorl is so weather resistant even outdoor. Tourmalines are not afected by acids in ambient temperatures and it can degradate to mica and/or clorite only under high pressure and temperature conditions.
For my own experience, is usual to find schorl in good shape in pegmatites even when feldspars are weathered. As I said, this is my experience, in other places and under other conditions things could be different.
Greetings.

[Luiz Menezes]

One of my first experiences as a starting mineral collector (on the 1960's) was to dig for schorl crystals in very narrow pegmatites on the shore of one of the water reservoirs ("Guarapiranga Dam") that supplies the city of São Paulo; there was also a small island, that we called "Island of Tourmalines", that was exposed only on the dry season, when the water level came down several meters, and then was accessible by boat; so schorl could survive perfectly under several meters of water under tropical conditions; it is chemically stable on our lifetime period, therefor, it may not resist extreme physical changes: it might crack if submitted to cicles of high heating by sun-light followed by sudden cooling.