![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/b6335c8607117.560c047ba0f51.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/0aa0548607117.560c049f22876.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/e5f53b8607117.560c049ec5ef2.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/87e3488607117.560c0447ef0cd.jpg)
Opal is a hydrated amorphous form of silica; its water content may range from 3% to 21% by weight, but is usually between 6% to 10%. Because of its amorphous character it is classed as a mineraloid, unlike the other crystalline forms of silica which are classed as minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl and basalt. (Wikipedia.org)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/ed33af8607117.560c03d52983c.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/84c1418607117.560c03d2c245e.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/0470df8607117.560c035e54457.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/0a3e018607117.560c044946d11.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/2ed3ad8607117.560c04494fcc6.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/5df0798607117.560c04a958350.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/12e2f48607117.560c06bd5856c.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/63b3518607117.560c067974f95.jpg)
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![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/4532a18607117.560c068d4a335.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/70ef998607117.560c049f556df.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/85aa3f8607117.560c064acda04.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/18e6458607117.560c064a8a919.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/afa0d58607117.560c06bd5f06b.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/b52a478607117.560c0580dbfa8.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/77a0788607117.560c06810e409.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/5167918607117.560c06bccd6c3.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/b859048607117.560c03655575f.jpg)
![close up macro mineral opal silica mineraliod gemstone rainbow gem fire red blue green limestone](https://mir-s3-cdn-cf.behance.net/project_modules/max_1200/e66cb98607117.560c049f810b5.png)