FMF - Friends of Minerals Forum, discussion and message board

[Screenname]

What would cause quartz to appear cloudy? I bought a piece at a garage sale and it was a pretty good sized piece but you can't see through it at all. I don't know if there is something on it or if it's like that naturally, I wish I had a picture of it to put on here to show you.

[alfredo]

This is sometimes due to millions of included microscopic bubbles of liquid and gas.

[Peter Megaw]

I agree with Alfredo, but might suggest it is USUALLY because of inclusions. It's actually more interesting to ponder why crystals are clear

[Screenname]

[Jason]

could be due to inclusions...could be due to a matte type finish on the surface...good be because it has bad "crystal"(atoms not arranged in a nice neat order)

[jacquestouret]

Cloudy quartz is a classic in fluid inclusion literature (in French, as atmospheric terms (nuageux, brouillardeux) do not sound very well, we prefer to call it "milky" (laiteux). If you want to remain in the atmosphere, foggy would probaly be better than cloudy, as the colour effect (Tyndall) is the same than caused by headlights in the fog (light difffusion on tiny particles). In quartz, these tiny particles (often improperly called "bubbles"), are myriads of fluid inclusions, typically less than 1 micron in size. They correspond to quartz defects in a rapidly growing crystal, in oversaturated mother solutions. In alpine-type veins, the base of many crystals is milky (rapid growth, at the opening of the vein), whereas the top, growing slowly at near equilibrium, is perfectly clear (and inclusion-free) (Hence the term "foggy bottom" would be appropriate, I just come back from Washington, DC!). Tip for finding nice inclusions in any quartz crystal: look at the transition zone between milky and clear. Good luck (you'll enjoy it!).

[Screenname]

Here I took a photo of the stone in which I was speaking