Geological Microscope Slide Troctolite (Coverack)

Thin Section Microscope Slide of Troctolite from Coverack, The Lizard in Cornwall. Known as 'Trout stone' on account of its attractive, multicoloured mottled appearance, it is a relatively rare rock. Showing olivine which is partly altered to serpentine, and part still unaltered which shows bright colours in xpl. The other mineral is plagioclase, easily recognised by its twinning, but slightly distorted. The red colouration is heamatite formed as a secondary mineral from iron in the olivine released by the serpentisation. This is an intermediate rock between the Gabbro and the serpentine, with parts of each in the rock. It is characteristic of the lithosphere - mantle junction known as the moho layer. Rarely seen, only when part of the oceanic crust is 'beached' on land as in the Cornish Ophilite at the Lizard. Spectacular under crossed filters and a much better slide than is shown in the photos.

A sample of the rock from which the slide was cut is included

The description is provided as a guide as to what to expect, but buyers should identify the rock type and minerals for themselves. Slides are prepared with the greatest of care, ground to the correct thickness, and covered with a glass cover slip. However if you are not satisfied with any slide I will refund the purchase price (except the postage) if you return the slide within 7 days