A rare arsenic-containing mineral which occurs as colourless to grey or green elongated crystals, often in polycrystalline masses.
Adelite is a basic arsenate of calcium and magnesium, CaMg(AsO₄)OH. Crystal system: orthorhombic.
Late 19th century; earliest use found in American Naturalist. From Swedish adelit from ancient Greek ἄδηλος indistinct + Swedish -it.