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Rutilated Quartz or Glass?

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Selkie
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Joined: 07/03/2011
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Rutilated Quartz or Glass?

This stone sure looks real but I don't know what it is, nor did the person at the store who sold it to me. But he said it was a stone of some kind. Maybe rutilated quartz, but then wouldn't it have needles in it?  I bought it today in a crystal (mostly manmade crystal) jewellery store that had lots of genuine stone pendants, like turquoise, jasper and agate, for the same price. This stone is basically clear but has  brown bits in it, it almost looks like little bits of brown algae from a lake.

I don't see any needles at all. I looked at it under a 10x loupe  and I saw a few small bubbles that aren't visible to the naked eye. I also saw in one area that there were quite a few very, very tiny bubbles.   There are also two tiny inclusions on the surface an a scratch on the bottom of it. Sorry for the poor quality photos, I can take more outside later when the light is better.

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Himanshu
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Joined: 01/12/2009
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Generally, rutilated quartz will have needle-like rutile crystals but it is also possible that rutiles are in form of small crystal without needle-like structure inside quartz. Rutile quartz will look something like this http://www.gemstonebuzz.com/sagenitic-quartz but not always.

However, if you are sure that those "small bubbles" you saw were "gas bubbles" i.e. not liquid and solid then most probably it is a man made glass. Glass bubbles are also present in natural glass but since they are pricey it is not likely to be a natural glass.

Are "tiny bubbles" which you saw through 10x loupe are all near to each other? If so, they can be fingerprints i.e., small crystal (solid) inclusions or liquid inclusions. Because normally (according to my experience), gas bubbles are scattered around at different places in gemstone. Gas bubbles also comes in different shapes (round, oval, elongated) and size (very small, small, large). But fingerprints generally stays in a group which are in almost similar shape and size.

The hardness of quartz is 7 and it is not easily scratch-able. Also the hardness of man made glass is between 5-6. So, scratch doesn't give a conclusive result. (But, if you had a sapphire and had a scratch in it then it most probably be a glass as sapphire has a hardness of 9).

I have seen many man-made glass which imitates exactly like real gemstone. Glass is the best simulant for any gemstone.

To get a conclusive result for this gemstone, a simple refractometer test will be enough. Just identify whether the stone is DR (i.e. quartz) or SR (i.e. glass) will dissolve your doubts. Refractometer is a must instrument for anyone who are in frequent purchases/sell/trade/lover of gemstones. Refractometer alone can distinguish almost 50% of gemstone simulants. More information at http://www.gemstonebuzz.com/refractometer

The quality of picture does not do a justice for this lovely stone, if it is real one. :-)