PPL Vesuvianite (idocrase)-rich contact altered limestone. Oxford Limestone in upper contact of the Whin Sill dolerite. Barrasford Quarry, Barrasford , Northumberland, NY919 749 Collected by B. Young 2005
High relief vesuvianite crystals (in centre and left) and high relief garnets towards top centre. Opaque carbonaceous? material. The visible part of the centre vesuvianite crystal is 0.75mm in length.

XPL The near centre vesuvianite (idocrase) crystal shows typical low order grey interference colours and is surrounded by calcite. The vesuvianite to the left is in the extinction position. Large isotropic garnet centre right and smaller ones seen towards top centre.

The hand specimen shows pink garnets (grossular) and dark carbonaceous material set in a calcium carbonate groundmass. The vesuvianite (or idocrase) is apparent only in the thin section. Vesuvianite occurs in thermally metamorphosed limestones and in skarns. It is associated with grossular, a calcium bearing garnet as well as diopside and wollastonite.


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