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Identity HelpColor changing Rock, but what kind of?

16th Sep 2019 15:26 BSTRubel Shahab

This rock is bluish black in indoor light but once taken to the window light it changes color to vivid orange/ golden. The changed color shown in the reply.

16th Sep 2019 15:28 BSTRubel Shahab

Normal day afternoon light from my window.

17th Sep 2019 01:39 BSTIan Nicastro

It appears to be Chalcedony or Agate. Although your first photo isn't bright enough to illustrate the blue, I know what you are talking about, and the 'color change' you see is due to this:

17th Sep 2019 01:38 BSTKevin Conroy Expert

Possibly chalcedony.   What is its hardness, and does it fluoresce?

17th Sep 2019 01:56 BSTPaul Brandes Manager

I would tend to say chalcedony as well.
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