Gabbro, Flow Aligned Eucrite, Ardnamurchan.

This is a thin section of Eucrite from the tertiary volcanic centre in Ardnamurchan, on the West Coast of Scotland. Famous for its complete ring dyke made of this material (or is it a Lopolith?). It is a gabbro consisting mainly of plagioclase feldspar, classic albite twinning, with large olivine crystals and pyroxene. This is a sample showing alignment of the plagioclase laths. These also show exceptionally sharp twinning. The pyroxene in this slide is interesting as, although it is only about 20% of the minerals by volume, it appears to be one large crystal, larger than the whole sample. This can be seen by the consistent XPL colour and the same extinction position of all the separate parts

More expensive than the standard Eucrite as this material presents certain production difficulties.

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