Madocite is a noun referring to a rare mineral that belongs to the pyroxene group. It typically occurs in metamorphic rocks, especially those formed in eclogite facies conditions. It is primarily composed of calcium, sodium, and magnesium silicates, with the chemical formula (Ca,Na)(Mg,Al,Fe,Ti)(Si,Al)2O6.
Madocite is typically found as small grains or aggregates within the rock matrix, appearing in shades of green, gray, or brown. It exhibits a prismatic crystal habit with a blocky or stubby appearance. The mineral has a vitreous to dull luster and is translucent to opaque. Its hardness varies between 5.5 and 6.5 on the Mohs scale, making it relatively hard.
This mineral was first discovered in the Handa mine located in the Madoc Township of Ontario, Canada, from which it derives its name. It has also been reported in other regions across the globe, including the Ural Mountains in Russia and various localities in the United States.
Madocite possesses satisfactory cleavage and a characteristic elongation along the length of the prism. It frequently occurs alongside other minerals like garnet, omphacite, and kyanite within eclogite rocks. Thanks to its unique composition and occurrence, madocite has attracted interest as a potential indicator mineral for determining the geological history and formation conditions of eclogite facies rocks.
