Amorphous gems

Amorphous gems are those minerals or rocks that do not have a regular the internal arrangement of atoms, characteristic of crystals. In the Greek language, amorphous means "formless", "not having a crystalline structure". Unlike crystals, amorphous substances do not solidify with the formation of crystalline faces, and possess an isotropy of properties, that is, they do not show differences in properties in different directions.

Amorphous gems are those rocks that do not have a regular the internal arrangement of atoms...

The amorphous state of many gems is obtained at a high rate of solidification (cooling) of the liquid melt from which amorphous gems formed.

The absence of a definite order in the arrangement of atoms leads to the fact that atoms in amorphous gems are combined into small groups, like particles in a pile of sand, which excludes the possibility of forming one or another form; therefore, such gems are never in the form of crystals. An example of an amorphous material is glass. Amorphous gems are opal and obsidian. Opal is a silica with a certain amount of water. Opal is characterized by different transparency and color. Noble opal shimmers with all the colors of the rainbow, fire opal - orange-red. Dairy and other opals are known. Amorphous gems, rocks and other minerals under breakage give a shell fracture.

Amorphous gems in nature are rare. The vast majority of representatives of the realm of minerals has a crystalline structure, although it is not always easy to determine.

Under external influences, amorphous gems exhibit elastic properties, like crystalline solids. So, for short-term impacts (strokes), they behave like solids and split into pieces in a strong impact. But with a very long exposure (eg, stretching) amorphous gems "flow" like a liquid.

Electrical properties of amorphous gems are closer to those for single crystals than for polycrystals due to the absence of sharp and highly contaminated intercrystalline boundaries with impurities, often with an entirely different chemical composition.