There is metal of some sort in black diamond. If you run a magnet up and down the bag you will hear tiny grains following it...... is it harmful to our fish ? Who knows !
Nonsense. People.. if you haven't got 1st hand experience with this stuff please refrain from FUD. This stuff is silky, not abrasive in any way. Yes it is BLASTING MEDIA but if you know anything about sandblasting you know that this stuff is on the bottom of the aggressive scale for it's purpose. No catfish is going to suffer from it. No iron is going to turn your hands black. There no no OIL in it. It is thoroughly washed before it's bagged. Some particles will tend to float when you put it into water but will settle quickly. If you read the NUMEROUS threads on here you will see that it's an inert sub with no CEC value that is suitable for just about any scape.
It is also NOT the same as Black Beauty. That is a different brand, and not to be confused.
People on the west coast have trouble getting it. You might want to call ATI (1-800-343-0117) and register your thoughts with them.