Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
3M Colorquartz is a very dense material, and very clean. It is my understanding it is off the market or perhaps being sold under a new name. There are similar products that are available. Look for the Pebbletech product line.
If you have access to 3M Colorquartz or equal, it is a nice material. I sure do not think it has any cationic exchange capacity, though. It is easiest to describe it as a very uniform sand or very fine gravel. It was available in many colors. I have one tank with the black Colorquartz. Really sharp looking.