RUBY CRYSTALS IN AMPHIBOLITE

Ruby crystals are scattered throughout this chunk of amphibolite. Amphibolite is a coarse-grained metamorphic rock that has amphibole minerals such as hornblende as the main ingredient.

Ruby and sapphire are both varieties of the mineral corundum. Red corundum is called ruby, while all other colours of gem-quality corundum, including colourless, are called sapphire.

An attractive and interesting specimen.  It is from an old collection and its origin is unknown.