I unearthed the stuff at a local sandblasting/contractor store. Call 3M to find a dealer. The stuff is about $18/bag. My sand was basically a fine sugar sand variety. I've had no deaths in my tank and have been using it for 2 months or so in my 125 gallon.
It was $18 per 50lbs bag. The fish love it. Since moving them into the sand over a month ago, I've had one fish die from unknown causes. The jewels LOVE this stuff as do my other malawi cichlids. I used about 2" across the bottom and they have created their own pits and mounds.
If you mix the black with another color in a 2/3 black to 1/3 color mix, it will overtake the black. I'll see if the wife can post pics of our 125gal with it. I have nicknamed the take, "The 125 gallon from Mars". We mixed thier red and black together and used red lava rock. The red matches the lava rock nearly perfect and since I overdid the red, it looks like the planet Mars. If you use any fake plants, I'd silicone them to the bottom. We didn't and the fish decided they liked all the plants in a different location, no matter if we moved them back or not.
I got the finer grade. It doesn't cloud the water and settles very quickly. I had a AC 500 go out and I haven't investigated the reason yet. It may have been the sand, but the other AC 500 is working fine and is nice and quiet.
Also, I found the black is probably a "flatter/duller black than the other black sands, but I also only have two 36" single strip lights to light my aquarium.
I buy all my sands from them. I've gotten great deals on 3M colorquartz (I was the one who initially stumbled on this product while buying my Red Flint sand from them.) They also have a Unimin sand, 50lbs for $6-7 that is near white. Red Flint sand and gravel is like $6/100lbs.
Wow! I haven't posted in months due to my upcoming deployment with the Army. I originally unearthed this product. Glad to see there are many who have tried the 3M colorquartz and like it for the looks and the price.