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GeneralJapan Law Twin

19th Dec 2011 21:59 UTCDanny Jones Expert

Can some one tell me the tech defination of a Japan Law Twin?

20th Dec 2011 00:23 UTCDavid Von Bargen Manager

It is a twin that has a composition plane of (11_22). There are actually 4 main twin types (that increases to ten if twin enantiomorphs are counted) called Japan twins. In one type this is the twin plane and in the other three it is a pseudotwin plane. It also depends upon the "hand" of the crystal (left or right) and the polarities of the a axis.

20th Dec 2011 15:07 UTCErik Vercammen Expert

An older name for the same twin is "La Gardette twin", after the French locality. The 2 crystals have an angle of about 84°30' between them and their main axises (the c-axis) are in the same plane. Often, the twin is flattened and/or heart-shaped.
 
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