posted on Jul, 4 2010 @ 04:22 PM
The white definitely looks like vein quartz, though at a push it could be calcite. Have you tested it with acid (hydrochloric 10%)? If it fizzes it
will be calcite.
Obviously the rock has been subjected to quite an amount of transport given the smooth shape.
The red 'country rock' looks like it could be a sandstone, but it's hard to tell without a handlens and actually holding the rock. Is the
groundmass made up of crystalline (well-formed crystal shapes) material or sub-rounded etc grains?
Without holding the actual hand specimen it is difficult to tell, but the 'quartz' looks like it is pressure-infilling giving hydrothermal fluid
flow a possibility. Certainly the white material (quartz/calcite) is a later occurrence than the surrounding material.
Where did you find it?
Where there other rocks of the same material?
You're in Scotland, yeah?
These links may help you and there should be someone you can contact, either at the British Geological survey, a museum, or a Geology Department at a