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[Scalebar]

I bought some moonstone a while back, I don't know what a sensible price is but at ten pounds a kilo for chunks around the 100g mark I was happy.

I've got a few reasonable stones and one stunner out of the 400g I bought, but most of it just fragments into square bits around 4mm - usually waiting until I'm happy with the cab shape before doing so.

Is that just what I should expect from moonstone and I should be happy considering how little I spent or was it just not great stone? Am I just a clumsy oaf?

I'm not having a whinge - but not having worked with it before, I have no idea how to gauge the quality.

[lithicbeads]

 Moonstone is fragile but not normally that fragile.I can't speak to your rough but a large moonstone deposit outside of Butte Montana was entirely destroyed years ago when the owner had it all drilled and blasted.I have seen large agate deposits blasted successfully because agate is less fragile and there was plenty to waste as too fractured.Moonstone is and was far more valuable and demands patience in extraction.

[gemfeller]

Moonstone is a member of the large feldspar family.  Feldspars have two cleavage planes that intersect at 90°. Fragments of pure feldspar crystals thus tend to form rectangular blocks with irregular ends.

Having cut my share of moonstone and other gemmy members of the feldspar family, they key thing is to avoid opening a cleavage plane.  That means very gentle grinding, avoiding any hard knocks.  Your cutting technique could be part of the problem.  You need to start careful grinding with no grit lower than 220 and be sure to use lots of water in that and subsequent operations. 

Even after cutting cleavages can be started by hard knocks when worn in jewelry.  I'd recommend pendants or pins and not rings.   

[Scalebar]

Thanks. I'll try starting off with the 400 plate this weekend and see how it goes