Inclusion (mineral)

Inclusions are usually rocks or other minerals, less often water, gas or petroleum. Liquid and vapor create fluid inclusions. In amber, insects and plants are common inclusions.

The analysis of atmospheric gas bubbles as inclusions in ice cores is an important tool in the study of climate change.{{Cite web|last1=Barnola|first1=J.-M|last2=Raynaud|first2=D.|last3=Lorius|first3=C.|last4=Barkov|first4=N.I.|year=2003|title=Historical Carbon Dioxide Record from the Vostok Ice Core|url=https://cdiac.ess-dive.lbl.gov/trends/co2/vostok.html|access-date=2020-08-08|website=cdiac.ess-dive.lbl.gov}}

A xenolith is a preexisting 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.

File:Dominican Amber housing an Insect.jpg, has gas bubbles protruding from its thorax and head.]]

File:Three Phase in Rock Crystal Quartz, Pakistan.jpg origin. The liquid encased is petroleum, and the gas bubble is methane.]]

Inclusions are one of the most important factors when it comes to gem valuation. They diminish the clarity and value of many gemstones, such as diamonds, and increase the value of others, such as star sapphires.{{Cite web|date=2017-01-20|title=Types of Mineral Inclusions with Photos|url=http://www.geologyin.com/2017/01/types-of-mineral-inclusions-with-photos.html|access-date=2020-08-08|language=en}}

Many colored gemstones are expected to have inclusions which do not greatly affect their values. They are categorized into three types:

• Type I colored gems, such as aquamarines, topaz and zircon, have very few or no inclusions.
• Type II colored gems, such as sapphire, ruby, garnet and spinel, often have a few inclusions.
• Type III colored gems, such as emerald and tourmaline, almost always have inclusions.

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.

{{see also|Casting defect#Inclusion (casting)}}

The term "inclusion" is also used in the context of metallurgy and metals processing.{{Cite web|last=Petersen|first=Christian|date=August 2, 2020|title=What Are Inclusions in Steel?|url=http://www.wisegeek.com/what-are-inclusions-in-steel.htm|access-date=2020-08-08|website=wiseGEEK|language=en-US}}{{Cite web|title=The Origins of Oxide Inclusions :: Total Materia Article|url=https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=378|access-date=2020-08-08|website=www.totalmateria.com}} 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.{{Cite book |last=Ashby |first=M. F. |url=https://www.worldcat.org/oclc/852806045 |title=Materials: engineering, science, processing and design |publisher=Butterworth-Heinemann |others=Hugh Shercliff, David Cebon |year=2019 |isbn=978-0-08-102376-1 |edition=4th |location=Oxford |language=en |oclc=852806045 |department=Department of Engineering, University of Cambridge, UK}}{{Cite web|title=Inclusion Metallurgy|url=https://metallurgy.at/en/inclusion-metallurgy/|access-date=2020-08-08|website=Department Metallurgy - Metallurgie Department|date=30 January 2019 |language=en-GB}}

• Diamond inclusions

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Category:Mineralogy

Category:Petrology

Category:Gemology

Category:Metallurgy