I sell this stuff at wholesale to lfs. Its very nice sand. I used it in my black ray tank 300 gal. I have it in other tanks also. I removed it from my 300 gal because it is very light and does get sucked up by filtration especially if you have cornerflows that suck from down low. The rays move around a lot and stir it up like crazy. It has a very nice shimmer especially under led lighting. Metallic effect. Ive never heard of it containing metal or actually being metallic... Sounds odd to me! I would recommend this product and it is actually my #1 seller of many substrates i distribute in canada for FW tanks. Cheers