Following my last posts, I've experimented more with sanguine. Results to date have ben very scratchy and the stick is a little too hard with gum tragacanth. My lastest result needed a considerable amount of grinding both in the mortar and pestle and with a muller. I think it could have done with even more griding but its hard work to produce really fine dust by hand.
I have discovered an old renaissance recipe using a weak honey solution as the binder. I've also tried this with other pigments and its very effective, others of you may have tried this. It significantly reduces the dust with some pigments but not so much with sanguine.
Sanguine in its natural form is tricky to work with and its said that the best sanguine lumps are now in very short supply and often contain streaks of other minerals. Certainly the samples I have are not pure.
Whilst its wonderful to work with the same materials as the masters, these days its probably better to use modern materials.