My Rockey Rock

My rock collection is special
because my mum brought it for me.
My rock collection is rough like sandpaper,
if it falls it will be with a crash,
also can end up with a bash.
Made thousands of years ago
or maybe millions of years ago,
it cuts into squares
found so deep in the ground.
Some of the many rocks down below
so old but looks young.
It may be the greatest treasure of all
so tough, it will never break.
In my collection I have 8 rocks;
It can come in many shapes and sizes,
You can hardly can call it a wimp.