Macle
Macle is a term used in crystallography. It is a crystalline form, twin-crystal or double crystal. It is crystallographic twin according to the spinel twin law and is seen in octahedral crystals of minerals such as diamond and spinel. The twin law name comes from the fact that is commonly observed in the mineral spinel.
Macle is an old French word, a heraldic term for a voided lozenge. Etymologically the word is derived from the Latin macula meaning spot, mesh, or hole.
