Difference between revisions of "Opal"
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− | [[Image: | + | [[Image:Precious_mexican_opal.jpg|left|framed|Precious Mexican Crystal Opal<br />Photo courtesy of<br />Rick Martin, Art Cut Gems]]<br clear="left" /> |
Revision as of 06:14, 27 December 2006
Opal | |
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Chemical composition | SiO2+.H2O |
Crystal system | Amorphous |
Hardness | 5- 6 1/2 |
Refractive index | 1.45 (+.020;-0.080) |
Specific gravity | 2.15 (+0.07;-0.90) |
Lustre | Vitreous |
Phenomenom | Play of Color |