Crinoids
There are a couple of different crinoids on this page from various localities around the world. They were all prepared with one of the air blasters that Ken sell's. They are an excellent finishing tool in most cases and would not normally be used to completely prepare a specimen unless it is some thing like these crinoids.
This is Scyphcrinites from Morocco, I have cleaned about a third of it at this stage.
The finished item, the blaster has really fetched out some fine detail on this crinoid.
This is a crinoid from China Traumatocrinus, just as I received it.
A few hours later and the crinoid is starting to immerge.
The crown and main arms are almost out, there is the top of another crown on the bottom left just out of view.
About another 5 hours and this one will be finished, I can then trim a couple of the outer edges up on the stone cutting saw.