What is Seachem Flourite made of?

[tankbully]

Ok I'm not sure where to start but what is flourite made of? Is it really a hard clay or some form of rock fragmentation? The reason I ask is because I have been pulling the rocks out of a flower bed, sifting the dirt and weeds out and putting back into place. Now what i have left in the bucket is what looks like seachem flourite, little fragments of red and black rocks irregular in shape and size. I'm told the rocks we cleaned out are sandstone or shale rock. Is this the same as flourite or am i getting my hopes up for a free way to deco my planted tanks?

[Tom Barr]

Clay mostly.

Not sure about what you have or not.......