How much water is in blue stone?

Question

It's for a Science Class. If you could tell me quickly how to find out , or answer the question it would help a lot. And no, I am not cheating...

Answer 1

To determine, weigh a freshly mined sample of the stone, then place in a drying oven and periodically re-weigh untill no further weight loss occurs. The difference in weight divided by original weight will give you a percentage by weight.

[(original wt-dry weight)/original wt] x 100% = weight % water