Knapping Experiment: advice needed please!

Hi! 

I am a PhD Student and I am planning to do an experiment on knapping in humans, but I am struggling to select appropriate stones, and I was hoping you experts could provide some advice please? 

Basically I am looking for stones that easily break conchodially (both when hit hard and softly), and ideally were also used to make early stone tools? Also, since I will be working with students, I would  really like a stone that 'sprays' in the least damaging way (where the tiny splinters flying off the core whilst knapping are either not sharp or few).


Does anyone what stone would be best for this? I realise I'm being very picky, but any advice would be greatly appreciated!


Thank you! 

In Britain almost all stone tools were made from flint, though other materials were used, especially in Scotland where flint is rare. 

Getting hold of any knappable material in Britain these days is difficult and flint is really the only relatively easy material to get hold of. Alternatives could be agate, pitchstone, chert and several Scottish materials, I know there is at least one chert quarry in the UK though don't know if it produces knappable material. Alternatively if you only need a small quantity, import from the US is an option, a wide variety of very easy to get hold of rocks is available there.

Basically flint is sharp, razor sharp, spraying of flint is not a problem for the knapper if safety gear is worn when knapping, but the shards if left on the ground can be dangerous. Most other material is less sharp, than flint, (glass excepted) the least sharp are softer cherts, but all knappable materials are sharp.

Thank you for your reply! very helpful. 

I have seen that a couple of studies also used porcelain, any experience with that? does it fracture conchodially like flint or chert? are the shards any safer? 

Thank you!

It's knappable but very difficult to knap, I've tried and failed. It's one of the less sharp material but still sharp. Is there a specific reason you don't want sharp shards?