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Difference between 2 specific minerals

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What is the difference between common opal and chalcedony?

asked Jun 3, 2014 by Outback Bob (120 points)

1 Answer

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Opal contains water in its chemical structure and is amorphous, whereas chalcedony does not contain any water and is microcrystalline. Opal's hardness is about 5.5 whereas chalcedony is 7. Hope this information is helpful.

answered Jun 6, 2014 by hershel (49,730 points)