Mineral experts- do you know what this rock I found is? (UK)?

Question

I'm in Cornwall, most of the rock around here on mine dumps is granite, with quartz and pyrite in, and metal ore that look to me like iron. I found this rock, it's a blue colour and has some pyrite in it- do you know what it could be;

[IMG]http://i120.photobucket.com/album...

Answer 1

It looks to me like Azurite a copper ore

http://www.flickr.com/photos/orbitaljoe/...

Answer 2

Bornite - also known as peacock ore - a copper sulphide.

http://www.galleries.com/minerals/sulfid...

Are there any freshly chipped surfaces that are a coppery red, if so,sure fire cert it is bornite as the fantastic blue colour is an interference effect resulting from tarnishing of the surface

http://www.theimage.com/mineral/bornite/...

EDIT- does it react with an acid (toilet descaler is what I use, but weak HCl if you have access. If so I concede to Jum, as it will be a carbonate.

Also, does it leave a coloured streak on the back of a tile?? if so, what colour?? ENDEDIT