What's a strange rock?

...I have a strange rock in my inventory. What exactly does it do?

Going to bed thanks for who ever knows, didn't feel like looking it up on runehq always lags =)

 

When you get 2 in every skill they come in. I believe it's all except combat related. You get:

1-) Exp for putting it into the statue
2-) Closer to a new statue (I.E. You can get 2 more stones in already earned skills)

When you complete the statue you get to make another one. Basically, you get experience for making the statue.

You can do this in Varrock Museum.

You need all the rocks to complete the statue

EDITED

 

Seems like a thorough answer.