Habit: Yellowish brown, brown, white, ash or yellowish gray, pale green or colorless. Commonly crystallized, typically rhombohedral to steep scalenohedral prismatic; also fibrous, stalactitic, spherulitic and fine-grained to massive. Vitreous luster, but may be pearly or silky; translucent. White streak.
Environment: A common component of bedded sedimentary iron ores and metamorphic iron formations. Also occurs in hydrothermal metallic veins.
Etymology: From the Greek word for iron, sideros, because of the iron in its composition. Siderite is used as a minor ore of iron, and also as a pigment when a red or brown color is desired.