3m color quartz is also really good... but, it will scratch your glass... i used it on an old cichlid tank i had... don't have pictures of it, it was like 10 years ago... it was heavier than any other sand available... the grain is heavy, and stays put... also, the poop doesn't go to the bottom... might be bad for microfauna...
here's a picture of a planted tank with the stuff...
oh shnap, i found my old cichlid tank.... LOL... two different types of gray color quartz sand in this tank...