Garnet Mica Schist

Garnet mica schist is a variation of mica schist, a metamorphic rock formed by medium grade metamorphism which is usually a combination of both heat and pressure applied to the original rock, often a clay, mud or shale. These rock specimens, like our standard mica schist samples from Scotland are composed mainly of muscovite mica, with minor occurrences of quartz and feldspar, however, these specimens also exhibit the presence of numerous garnet crystals, which can be seen as red dots on the rock. These garnets are known as porphyroblasts, and suggest that the environment of formation was at or in close proximity to a convergent plate boundary with medium grade regional metamorphism taking place. The garnets are stronger than the muscovite crystals and so in some instances, it will appear as though the garnets are pushing the mica crystals around it, this can be seen much more easily in the cut and lacquered specimens if preferred. These rocks come from Loch Tay, a region in Scotland and are available in various sizes and as a 3 inch size piece with a cut and lacquered face to detail the crystal structure inside. Specimens will be supplied in a card tray with an information label.