A dark brown rock-forming mineral containing cerium, titanium, and niobium; now also more fully "aeschynite-(Ce)". Also: either of two related minerals, in which cerium and calcium are replaced either by yttrium, erbium, and calcium (more fully "aeschynite-(Y)"), or else by neodymium and cerium (more fully "aeschynite-(Nd)").
Aeschynite is an oxide and hydroxide of several elements with the basic formula AB₂(O,OH)₆, where A is one or more rare earth elements, calcium, ferrous iron, and thallium, and B is titanium and niobium. An older name for aeschynite-(Y) is
. Crystal system: orthorhombic, but the mineral is usually metamict in its natural state.
Mid 19th century; earliest use found in Edinburgh Journal Science. From German Aeschynit from Swedish äschynit from ancient Greek αἰσχύνη shame, dishonour, disgrace (from αἰσχύνειν to dishonour) + Swedish -it.