Id please.

Can anyone id this please. From the Gravel Hill Mine, Perranzabuloe, Cornwall.
The xtls shown are the only ones I can photograph. These ones are stained, others are white. When touched with a syringe needle they crumble, are colourless to white inside and appear partly hollow. They did not effervesce in HCL and Sulphuric acid had no discernible effect.

Approx 1mm long.

Bill G



Edited 2 time(s). Last edit at 04/11/2007 07:23PM by Bill Gordon.

Pyromorphite?

Perimorph/pseudomorph after ? (Xtal shape reminds a bit of mottramite/descloizite; does the shape agree with orthorhombic symmetry?)

It's difficult to tell the crystal shape from the picture, but it reminds me a bit of calcite, siderite, etc. However, needle tin may also have a similar shape (but is not likely to occur at Gravel Hill Mine). The actual mineral might be chalcedony. Chalcedony casts after a number of minerals are not uncommon in Cornwall.

Hi all,

I'm no good at crystal forms but, they have a shorter A axis than the B axis while the C axis is much longer than B.
Cross section is like a "diamond" shape with two // short sides and two // longer sides.
Associated with Cerrusite and Galena.

Bill G

Your description and this assocation may indicate a peri-/pseudomorph after anglesite.

Cheers Uwe.

Bill G

I have better pic's of the above to post but when I try to attach the file I get


"You have reached the maximum allowed number of attachments"

I see it worked though.

Bill G



Edited 3 time(s). Last edit at 10/14/2007 11:40AM by Bill Gordon.

different area and xtl form

Bill G

An enlarged view

Bill G

It is typical wulfenite from my point of view.

Probably siderite, Bill...

Another specimen.

Bill G

Looks to me like Titanite.

Hi All.

The NHM London have identified the above as Anglesite.

Cheers

Bill G