FMF - Friends of Minerals Forum, discussion and message board

[Leo]

Hello,

I have a question about a sample of mined quartz crystals. I have read about them on the Internet and found several applications including semiconductors, solar and TV panels, and jewelry, but still not sure which one this sample belongs to.

What is the right qualitative category of those rocks?
What is their most feasible practical application?

The facts below based on an expert assessment can be of some help.

Thanks and regards,

Leo



Origin: Brazil
Dimensions: 10-80 mm
Mohs scale: 7
Density: 2.6 kg/m3
Color: colorless; white; muddy watery
Colorless is a prevailing fraction
Fracture: conchoidal, uneven
Syngony: trigonal
Light refraction: 1.544-1.553
Chemical composition (%):
SiO2 Al2O3 Na2O MgO K2O CaO P2O5 S TiO2 Fe2O3 MnO
99.79-99.87 0.11-0.19 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 0.01-0.02 <0.01 <0.002
Chemical composition (ppm):
Ba Cr Sr Zr Rb
26-240 5-78 13-16 12-15 4-7

[SteveB]

Be careful, this forum won't discuss anything to do with values and as for practical use of your photo examples is maybe for gravel lining and garden decoration. The practical application you mention i don't believe are ever from found or mined quartz, actually cheap emery paper is commonly made using crushed quartz and garnets, the ones you show made homemade crappy Jewlery pendants. The really practically used quartz is lab grown for physical characteristics needed for practical use maybe original protypes for application started with natural quartz but it's an impractical method, so if you are thinking you have a box of highly valuable quartz you just don't. We are interested here in interesting and naturally formed minerals and there’s sign of anything interest on those terms here, it's just quartz, basically the most common and worthless mineral on the planet.

[Leo]

Thanks for your feedback. Concerning your comment about lab-grown quartz, I've heard that mined quartz is used as a raw material in a production of a final substance used for LED screens and solar panels. I'm seeking a more pointed feedback here in hopes there are forum users familiar with such applications.

[SteveB]

I thought I had given you the answer. Quartz used in anything practical today is basically industrial or lab grown to the characteristics needed. NOT mined for that purpose though it may have been mined once, just not anymore. Most electrical devices since World War II require oscillators, a small chip that vibrates and is required for the timing of electronic circuits. It's why your watch has Quartz written on it. It uses a quartz crystal oscillator. Your computer runs at 3ghz right? That's because a timing chip controls it, so that all parts of the computer stay in step. Yes, they started originally with mined quartz but not anymore. LCD screens definitely require a timing chip so pretty much every electronic device can be listed as having quartz in it. Quartz can also be crushed since it's a pure form of silicate (that's another hint: the silicon chip) and is a clean raw material for making glass of all sorts, sand off a beach isn't suitable). There are literally billions of products you can find that contain quartz though not in the size or form it comes out of the ground. Plus, white quartz is a common holder of metals and gets mined for its gold, silver and lead content, crystal quartz doesn’t.

[James Catmur]

You can make glass from it - the sand mine in Lochaline, Scotland tends to produce the very high quality sand needed for glass

https://lochalinequartzsand.co.uk/products

It is amazing to visit a sand mine (not a quarry)!

[Bob Morgan]

There's another mine near Spruce Pine, North Carolina, that produces high quality silica for the chip industry - much easier to purify than beach sand and much easier to get into fine grain than quartz crystal.

[silvia]

The element silicon is produced using high grade (very pure) Quartz or Quartzite and very pure carbon feedstock. You cannot use beach sand as it contains too many impurities, which end up in the Silicon. The actual energy required to produce Silicon is enormous as it is produced in an arc furnace using graphite rods. So, your Quartz might be a candidate for the making of Silicon.

[Matt_Zukowski]

Am I the only one frustrated by this thread? Some guy shows us a box of broken up quartz rock, lists a bunch of characteristics that are mostly, seemingly just generic for quartz, and asks us if this material has any use. Then Steve B answers his question saying that the material in the box likely has no commercial use and warns about us not wanting to talk value. Then the guy comes back and asks again about what use his material has. Then people trying to be helpful chime in with uses for quartz, but not the specific quartz in question.

It seems like this guy wants desperately for one of us to state some way in which his box of rocks has value. I am no expert but I suspect that quartz as a feedstock for an industrial process must come from a large enough deposit of very consistent quality, so that the refining process can be optimized. No one wants some guy’s box of broken up quartz rocks.

I vote we abandon this thread.

[silvia]

[Jordi Fabre]