Orthoclase - Carlsbad Twin
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EXAMP2
Data entry in this example follows almost exactly the same sequence as the last example, except that multiple forms are entered in the Add/Revise Form dialog. Use the Next/New button when finished with each form.

The Crystal system is monoclinic, and you can use the true axes, which are A=8.56, B=12.96, C=7.21 and BETA=115.83. This type of twin is usually drawn in a distorted habit, so it is not possible to use the full point group symmetry, which is "2/M" - instead enter "2". The forms present (indices followed by central distance) are:

   1)    {110}    1.0
   2)    {1-10}    1.0
   3)    {001}    1.6
   4)    {20-1}    1.3
   5)    {010}    0.8
   6)    {0-10}    0.4

The twin is type Interpenetration with intertwin edges: the operation is rotation by 180 degrees on axis [001]. Select Remove Hidden Lines from the Display menu to remove extra lines. It does no harm to leave this option on - it is ignored for single crystals.