Synth? (AlOx?) Stone ID

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Another one I grabbed as part of a stone lot with very little info on the listing. feels similar to the touch as a fine India, much darker in color, I put it next to a medium tiger head and a newer course/fine combi for comparison. Similar in hardness to an India (loose SiC for lapping didn't do terribly much) relatively quick to raise a burr when I put a knife to it. Atoma made a ligher slurry than the stone itself; let me know if you have an idea on what it is:

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What makes you think it's a synth? I'd guess a natural...

(And if that's the colour fully cleaned up then I'd be fairly confident.)
 
What makes you think it's a synth? I'd guess a natural...

(And if that's the colour fully cleaned up then I'd be fairly confident.)
I don't know if it's a synth, it could be a very hard natural? That is the color all cleaned up, even the missing corner shows it's that color. If it is a natural, what could it be? I can nab a SG reading on it if that'll help narrow it down.
 
No idea, but all the knives in the background make me happy! Nice storage containers too, I like the setup
I'll have to get a WIP post going for at least the batch I'm trying go clean up for my brother, and then probably another for rest since I've already got some directional questions on a handful of them. I am on vacation through the weekend, so I'll see if I can get something up.
 
I don't know if it's a synth, it could be a very hard natural? That is the color all cleaned up, even the missing corner shows it's that color. If it is a natural, what could it be? I can nab a SG reading on it if that'll help narrow it down.


Good idea - if you measure the SG then I'll try to give you an idea of at least what kind of rock it is. And then you could go from there, in having a look at options.

It's ever so difficult (impossible) to tell one dark natural stone from another in pictures, it could be anything really. I'm guessing a fine schist, maybe. Or what about those 'black arks' that RH Preyda sell that are actually a type of slate? Can't remember what they're called, but they have a name...
 
Good idea - if you measure the SG then I'll try to give you an idea of at least what kind of rock it is. And then you could go from there, in having a look at options.

It's ever so difficult (impossible) to tell one dark natural stone from another in pictures, it could be anything really. I'm guessing a fine schist, maybe. Or what about those 'black arks' that RH Preyda sell that are actually a type of slate? Can't remember what they're called, but they have a name...
Well the SG on that unknown stone is ~3.23, which means it's incredibly heavy for how large it is (and I can attest it feels that way). I also measured the washita and it's ~2.31, which I'm very excited about.
 
Well the SG on that unknown stone is ~3.23, which means it's incredibly heavy for how large it is (and I can attest it feels that way). I also measured the washita and it's ~2.31, which I'm very excited about.

3.23 ?!?? Umm... yeah I dunno.

Gimme a sec. I don't think I've ever done done SGs on these two, I'll report back...

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(2.31 is a lovely space for a Washita to be in, nice :)).
 
Well the SG on that unknown stone is ~3.23, which means it's incredibly heavy for how large it is (and I can attest it feels that way). I also measured the washita and it's ~2.31, which I'm very excited about.


Ok so... 3.23 is wildly higher than any stone I've tested, with the exception of Coticules which can get there because of the garnet. Given that yours clearly isn't a coti, then looking here:

https://www.gemfame.com/gemstone-specific-gravity-chart/
There's not much else (afaik) that gets made into whetstones which it could be, apart from:

Jadeite @ 3.3. And it's probably fair to say it's not that either.

Corundum @ 3.9. This is the natural form of Aluminium Oxide that 'Alundum' synthesised, so it could be an AlOx based synth.

or... the SG of Silicon Carbide is 3.22. It could be a very compact / pure SiC based synth.

Most likely a combination of the two I guess - some kind of vitrified SiC+AlOx stone.

Pretty unusual whatever way you spin it! The SG of Norton Crystolon or India stones is far lower.
 
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I'm going to guess that it's AlOx with a binder that keeps it very tight. I was playing around with it seeing if it could make any progress in flattening a course/fine India combi and it made significantly more progress than doing it for the same amount of time on a tile with loose SiC. At the very least it's quite interesting to have around and I'll mess with it on edges and also on flattening stones and see if I pick up anything else interesting about it.
 
I'm going to guess that it's AlOx with a binder that keeps it very tight. I was playing around with it seeing if it could make any progress in flattening a course/fine India combi and it made significantly more progress than doing it for the same amount of time on a tile with loose SiC. At the very least it's quite interesting to have around and I'll mess with it on edges and also on flattening stones and see if I pick up anything else interesting about it.
So it's like a barber hone in brick format.
 
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