Their hardness, insolubility in acids and the presence of unmixing bands usually distinguish them from other minerals except plagioclase. Distinguishing them from each other with the naked eye is often difficult: microcline, the amanzonite variety, can be distinguished quite well from the other two by its green color. Sanidine by its paragenesis, since its origin is volcanic, while the other two are mainly plutonic.
Generally, potassium feldspars are generated depending on the temperature of the magma and the cooling rate of the magma. Thus, sanidine is more stable at higher temperatures (over 900 ºC) and is characteristic of very rapidly cooling volcanic rocks such as trachytes, rhyolites and phonolites. Orthoclase is stable at an intermediate temperature, below 900 ºC, it appears in somewhat slower cooled rocks, such as acidic and intermediate igneous rocks (pegmatites, granites, syenites, granodiorites, etc.), also in high grade metamorphic rocks such as gneisses. Microcline is characterized by a lower symmetry (triclinic), because it is formed when the magma cools slowly, therefore it is a characteristic mineral of granites and syenites formed at great depth.
Opaque, translucent and transparent bodies for children
Decades ago, amethyst was also considered as a precious stone, but after the discovery of huge deposits in Brazil, it became part of the group of semi-precious stones, as it was not so scarce and rare.
Its name comes from the Latin ruber, which means red. Its main characteristic is the intense and bright red color that its name indicates. This color is due to the metals that compose it, iron and chromium. It belongs to the corundum family -just like sapphire- and has a hardness of 9 on the Mohs scale. It is the hardest stone after diamond.
When mined in the wild, rubies have a coarse and rough appearance, but once selected for use in jewelry and after being cut, they take on that unique radiant hue that makes them so majestic. It should be noted that only 1% to 5% of rubies extracted from nature are selected for use in jewelry.
Like ruby, it belongs to the Corundum family. Its distinctive feature is its intense blue color; although there are sapphires of other shades, the most valued and appreciated is the blue sapphire. Any corundum color other than red is called sapphire; hence it is adjectivized and called blue sapphire.
Management by objectives is a management technique through planning and administrative control based on the fact that, in order to achieve results, the organization first needs to define what business it is operating in and where it intends to go. The APO is a process by which the managers, principal and subordinate, of an organization identify common objectives, define the areas of responsibility of each one in terms of expected results and use those objectives as guidelines for the operation…
Production is the economic activity that provides added value by creation and supply of goods and services, that is, it consists of the creation of products or services and at the same time the creation of value, more specifically it is the capacity of a productive factor to create certain goods in a determined period of time.
I think that materialists have a completely opposite view of nature and reality to idealists. They believe that everything that exists is material or depends on matter to exist. The real world is out there, not in the mind. In order for a person to survive in his environment he must cease to be a slave and become a “man”, therefore he must be an active subject, that…
The cell is opaque transparent or translucent.
There are many varieties of quartz, several of which are used as gemstones, usually of relatively low value. The macrocrystalline varieties are classified by color, and the most abundant and most widely used have names of their own:    Their weathering occurs by dissolution, which concentrates in fractures in which they are concentrated.
 Their weathering occurs by dissolution, which is concentrated in fractures and at sites of crystal dislocation. Dissolution leaves crystallographically oriented triangular-shaped chemical attack pits. In a rock, the residual quartz grains that remain as weathering progresses are generally smaller than the initial grains or crystals. Some research reports increases in the angularity of quartz due to weathering, although there is also research that indicates the opposite. In addition, there is research that indicates that quartz has a higher angularity than the initial grains or crystals. In the same rock, there is also research that indicates the opposite. In the same rock, there are also research that indicates the opposite.