One easy way to tell if you get green wood or not is if it is completely covered in wax when you get it. If it is, it is green and needs to be dried.
Another way is to use a moisture meter. Some are not too bad in price, but still they are not cheap. It will tell you the moisture content anyway.
The last way, but you have to sacrafice a chunk of wood is to drill it and turn it kind of thin walled and set it aside for a few days to a week. If it is wet, it will warp and you will know.
Some woods turn differently that others. Blackwood can produce the most wonderful strands of wood when turned. I dont think how the curls come off the lathe mean much, but I could be worng on this.
Al @ THO