macle
/ˈmak(ə)l
/noun
1A diamond or other crystal that is twinned.Almost all the creeks that have produced gold crystals have produced triangular spinel-twinned crystals or macles....
- Flattened contact twins are known in the gem trade as macles.
- Good brown macle twins up to several carats in weight have been available in recent years from the Udachnaya mine.
2 another term for chiastolite.The chiastolite, or macle, shows the representation of a cross on its surface, this effect being produced by the regular arrangement of carbonaceous impurities along the axes of the crystal....
- The variety chiastolite (also called cross-stone, or macle) forms long prisms in a cross section.
Origin
Early 19th century: from French, from Anglo-Latin mascula 'mesh'.