Cleavage mineral crystals often break along a certain direction after being stressed, resulting in a smooth plane, which is called cleavage. Cleavage can be used to distinguish different minerals, different crystalline minerals, and the number, perfection and included angle of cleavage are different. Using this characteristic, different minerals can be distinguished between samples and microscopes.
Gem is the most beautiful and valuable rock. They are bright in color, crystal in texture, brilliant in luster, hard and durable, and rare. They are natural mineral crystals that can be used to make jewelry, such as diamonds, crystals, emeralds, rubies, sapphires and gold emeralds (rocks, cat's eyes). There are also a few natural mineral aggregates, such as agate and opal. There are also a few organic substances, such as amber, pearls, corals, coal powder, ivory, etc., which are also included in the broad sense of gems.
The reflection and luster of cleavage plane, the integrity of cleavage plane, the number of cleavage plane groups and their included angles, the spatial form of cleavage plane, and the relationship between cleavage plane reflection and mineral particle size constitute the attributes of mineral cleavage. These properties have different properties in different gem minerals or the same gem mineral, so they can be used for gem identification, especially for naked eye identification of jadeite.
Cleavage is also one of the bases for gem identification, and only a few gems have obvious cleavage, such as diamonds and topaz. Cleavage of diamonds: completely octahedral; Topaz Cleavage: A Group of perfect cleavage on the Bottom. Due to the development of cleavage at the bottom, one end of the crystal is often conical and the other end is flat. When machining, the mesa should be inclined to the cleavage plane for more than 5 degrees, otherwise the facet will not be polished easily. Sapphire and ruby are not cleaved. ...