Mica gneiss is a specific type of metamorphic rock that has undergone significant pressure and heat deep inside the Earth. Like other types of gneiss, it has a distinctive pattern of alternating light and dark bands, making it easy to recognise in nature.

Mica gneiss gets its name from its key mineral, mica, which gives the rock a shiny and sparkly appearance. Mica is a mineral that flakes into thin, reflective layers, creating an illusion of tiny mirrors in the rock.

In Estonia, gneiss is more commonly found as glacial erratics than granite.

Task: Examine this rock closely. Can you find the sparkling flecks in the rock? These are mica flakes. Use your phone’s flashlight to highlight the sparkle and make the mica easier to find.