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Inclusions are one of the most important factors when it comes to gem valuation. In many gemstones, such as diamonds, inclusions affect the clarity of the gem, diminishing the value. In some gems, however, such as star sapphires, the inclusion actually increases the value of the gem.
Many colored gemstones are expected to have inclusions, and the inclusions do not greatly affect the stone's value. Colored gemstones are categorized into three types as follows:
*Type I colored gems include gems with very little or no inclusions. They include
File:Gem with inclusion.JPG, Clear gemstone with metallic inclusion.
File:Peridotgem.JPG, Peridot with milky inclusion.
File:Ruby gem.JPG, Natural ruby with inclusions.
In mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...
, an inclusion is any material that is trapped inside a mineral during its formation. In gemology, an inclusion is a characteristic enclosed within a gemstone, or reaching its surface from the interior.
According to Hutton's law of inclusions, fragments included in a host rock are older than the host rock itself.
Mineralogy
Inclusions are usually other minerals orrock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wales ...
s, but may also be water, gas or petroleum. Liquid or vapor inclusions are known as fluid inclusions. In the case of amber it is possible to find insects and plants as inclusions.
The analysis of atmospheric gas bubble
Bubble, Bubbles or The Bubble may refer to:
Common uses
* Bubble (physics), a globule of one substance in another, usually gas in a liquid
** Soap bubble
* Economic bubble, a situation where asset prices are much higher than underlying fundame ...
s as inclusions in ice core
An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ic ...
s is an important tool in the study of climate change.
A xenolith is a pre-existing rock which has been picked up by a lava flow. Melt inclusions form when bits of melt become trapped inside crystals as they form in the melt.
Gemology
Inclusions are one of the most important factors when it comes to gem valuation. In many gemstones, such as diamonds, inclusions affect the clarity of the gem, diminishing the value. In some gems, however, such as star sapphires, the inclusion actually increases the value of the gem.
Many colored gemstones are expected to have inclusions, and the inclusions do not greatly affect the stone's value. Colored gemstones are categorized into three types as follows:
*Type I colored gems include gems with very little or no inclusions. They include aquamarines
Aquamarine is a pale-blue to light-green variety of beryl. The color of aquamarine can be changed by heat.
Aquamarine has a chemical composition of Be3Al2Si6O18, also containing Fe2+. It has a hardness of 7.5 to 8. Aquamarine contains no or few ...
, topaz
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...
and zircon.
*Type II colored gems include those that often have a few inclusions. They include sapphire, ruby, garnet and spinel
Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals.
Properties
S ...
.
*Type III colored gems include those that almost always have inclusions. Gems in this category include emerald
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p ...
and tourmaline.
Metallurgy
The term "inclusion" is also used in the context of metallurgy and metals processing. During the melt stage of processing particles such as oxides can enter or form in the liquid metal which are subsequently trapped when the melt solidifies. The term is usually used negatively such as when the particle could act as a fatigue crack nucleator or as an area of high stress intensity.See also
*Diamond inclusions
Diamond inclusions are the non-diamond materials that get encapsulated inside diamond during its formation process in the mantle. The trapped materials can be other minerals or fluids like water. Since diamonds have high strength and low reactivi ...
References
{{reflist Mineralogy Petrology Gemology Metallurgy