Black beauty is not the black equivalent of playsand. Play sand is quartz sand and black beauty is coal slag.
The 'aquarium' sands you find at pet stores are good but can get expensive for bigger tanks.
Other good options for colored sand is 3m Colorquartz (no longer being made but still in stock in some places), spectraquartz, or estes. Estes is often the stuff in LFS being labeled as aquarium sand and you can buy this in 50lb bags through an industrial supply company.
A company local to me carries this stuff in 50lb increments at about $25 per with 2 different grain sizes and a multitude of colors.
With all sand you'll need to wash thoroughly or you will have clouding issues from all of the dust.
And no, there is no clay in basic play sand.