Macle

Macle, a term employed in mineralogy to designate what are also called twin crystals, which are crystals united according to some precise law, yet not having their faces and axes parallel, so as to render the one a mere continuation of the other. In some macles the axes are parallel; in some, they are inclined at an angle. Crystallisation in macles is very characteristic of some minerals.—Macle is also the name of the variety of Andalusite (q.v.) called Chiastolite, a silicate of alumina, containing a little magnesia and oxide of iron. Macle has been much used for making beads for rosaries, &c.