Blackish grey crushed gravel substrate?

[phin]

Looking for something to put on the bottem of my tank that has a crushed slate look to it. Can I actually used crushed slate?

Also, where would be the cheapest place to go to acquire this material?

 

[Aquanero]

I don't have any experiance using crushed slate nor have I ever heard of anyone using it. I would think it would too sharp to use as a substraite. The closest you might come to the look your after might be black gravel mixed with Tahitan Moon Sand. Maybe someone else has a better idea.

 

[phin]

I forgot to mention that I do run an under-gravel filter...... I would imagine that would put sand out of the question.