Graemite is a rare and distinct mineral, classified as a silicate. It is a member of the epidote group and is typically found in metamorphic rocks, particularly those formed under high-pressure conditions. The mineral was first discovered in the Larsemann Hills of East Antarctica, named after the geologist Fred Graeme, and hence is known as "graemite".
The physical appearance of graemite can vary, but it is commonly found in greenish to brownish hues, with a vitreous to resinous luster. Its crystal structure belongs to the orthorhombic system, characterized by three unequal axes at right angles. Graemite typically occurs as prismatic, elongated crystals, often twinned, and may also be granular or massive in form.
Chemically, graemite contains significant amounts of silicon, oxygen, calcium, aluminum, and iron, along with trace impurities of other elements. Its chemical formula is generally written as Ca₂Al₃(SiO₄)₃(OH).
In terms of its geological significance, graemite is an important indicator mineral, assisting in the identification and classification of rock formations. It commonly occurs alongside other metamorphic minerals such as garnets, feldspars, and quartz. Due to its rarity and limited occurrence, graemite is primarily sought after by mineral collectors and researchers studying the geological history and processes of the regions in which it is found.
