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Can You Cast Granite?

If granite can melt (it can it becomes magma) [1], then can it be cast or blown like glass?

A look at the melting temperature of granite reveals that it is something higher than soda-lime glass, but lower than borosilicate! And it turns out that if you control the cooling rate of the material you can determine its crystalline structure. [2] You also control the structure of soda-lime glass by controlling the rate at which you cool the material to room temperature. [3] However, it remains to be understood how slowly it would need to be cooled to form a rock with the properties you would want.

But, I want to challenge the notion that glass is only cast or blown, and rock is only carved.

Also I read in the news that the covid vaccine vials are being manufactured with a "new" glass which is based on Aluminum [4] and is being used as an alternate to borosilicate. [5]

Granite has a fairly high proportion of Aluminum. So I also want to compare granite to a couple of clear, glass-like materials which contain aluminum: Aluminosilicate [6] and Aluminum Oxynitride [7].

Let's take a look at these materials:

Name Silica, Si02 (%) Alumina, Al2O3 (%) Glass Transition, Tg (degF)
Granite 72 14 Approx. 2300
Soda-Lime Glass 74 1.3 1063
Borosilicate 80 2-3 3000
Aluminosilicate 52-60 15-25 ?
Aluminum Oxynitride 0 30? 3900

Very interesting! At first glance it is so similar to aluminosilicate I don't see why it couldn't be cast. But the fining agents will make a huge difference.

From another point of view one could say we are already casting/blowing granite, as aluminosilicate.

Questions that come to mind regarding casting the opaque stone:
1.) What is the minimum annealing time required?
2.) Is it easy to work with?
3.) What kind of COE does it have?
4.) Is it a robust material, resistant to cracking or shattering?
5.) And does it age well, without oxides?
6.) Does it fair well with additives (e.g. cobalt) for coloring?


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