Just a rock?

[Mexico]

Here is another rock i picked up. Not sure but it don't look like anything good. Please let me know what you guys think. So far this site has been Awesome with helping me.

 

Amazon Forum Fav 👍

Minelab PRO-FIND 35 Waterproof Pinpointer Metal Detector for Experts with Tone ID & Adjustable Sensitivity - Grab it through Amazon!

[jackjones]

looks like calcite with some staining to me

 

[Mexico]

Cheers, Its vary hard, is Calcite normally hard?