twinning

Introduction References & Edit History Related Topics

Images

Diagram showing several shapes of natural calcite crystals. The top section illustrates four untwinned crystal habits, each with different geometric forms. The bottom section displays two examples of twinned calcite crystals, highlighting how their structures differ. Red dashed lines and axes indicate symmetry and orientation.

Relations between lamellar twinning and cleavage planes in dolomite and calcite. This difference can be discerned best when thin sections of the minerals are viewed under a microscope.

Figure 2: Twinning in feldspars.

twinning: Media

crystallography

Images

Diagram showing several shapes of natural calcite crystals. The top section illustrates four untwinned crystal habits, each with different geometric forms. The bottom section displays two examples of twinned calcite crystals, highlighting how their structures differ. Red dashed lines and axes indicate symmetry and orientation.

Calcite crystals occur most commonly in cavities in rocks, in vesicles in igneous rocks, and lining partially filled fissures.

Figure 2: Calcite crystals. Some of the many fairly common crystal habits...

Encyclopædia Britannica, Inc.

Relations between lamellar twinning and cleavage planes in dolomite and calcite. This difference can be discerned best when thin sections of the minerals are viewed under a microscope.

Relations between lamellar twinning and cleavage planes in dolomite and calcite....

Encyclopædia Britannica, Inc.

Figure 2: Twinning in feldspars.

Figure 2: Twinning in feldspars.

Encyclopædia Britannica, Inc.

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