Post by 1dave on Oct 17, 2024 17:41:57 GMT -5
Amazonite is an attractive gemstone known for its distinctive blue and green color. It is a variety of potassium feldspar called microcline. It was first discovered in the Amazon Jungle. Its chemical formula is KAlSi₃O₈, indicating it is composed of the elements potassium, aluminum, silicon, and oxygen. Among other places, it is found in the Pegmatites of western Colorado, where it is often found with smoky Quartz.
Where the microcline has schiller and exists in oligoclase or orthoclase, it is considered moonstone colored with microcline. When the microcline has no schiller, then it is considered amazonite. There are samples called amazonite that had schiller, and visa versa. Which is entirely confusing, because the nature of moonstone is such that it needs to be cut on a certain plane in order to get the schiller. So, if the stones that can exist in both categories are cut in a direction against the schiller, are they then amazonite?
The hardness can vary greatly from a very soft almost calcite consistency to a harder almost quartz-like quality.The white material, depending on how hard it is (again, it can vary) can undercut, so be prepared to re-break or shape with your saw. Also, if there are any quartz crystals mixed in, which does occur, it can undercut in those areas.
Moonstones are formed through a combination of magmatic and hydrothermal processes. The process begins with the crystallization of magma, which produces a variety of igneous rocks such as granite and pegmatite. During the cooling and solidification of the magma, feldspar minerals such as orthoclase and albite crystallize and form interlocking crystals within the rock.
The formation of moonstone requires an additional process, known as exsolution, which occurs during the cooling of the feldspar crystals. Exsolution is a process where one mineral separates from another mineral within a crystal structure due to differences in chemical composition or temperature. In the case of moonstone, the orthoclase and albite feldspars separate into alternating layers, which causes light to scatter and produces the characteristic adularescence effect.
Growth pattern:
It all depends on which, and how the atoms attach to each other.
