Editing Amethyst (section)

==Synthetic amethyst==
[[Gemstone#Synthetic and artificial gemstones|Synthetic]] (laboratory-grown) amethyst is produced by a synthesis method called hydrothermal growth, which grows the crystals inside a high-pressure autoclave.

Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same as those of natural amethyst, and it cannot be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). One test based on "Brazil law twinning" (a form of [[Crystal twinning|quartz twinning]] where right- and left-hand quartz structures are combined in a single crystal<ref>{{cite web
 |url = http://quartzpage.de/crs_twins.html
 |title = twinning crystals
 |website = Quartz Page (quartzpage.de)
}}
</ref>) can be used to identify most synthetic amethyst rather easily. Synthesizing twinned amethyst is possible, but this type is not available in large quantities in the market.<ref name="WiseSecrets1"/>

Treated amethyst is produced by [[gamma ray]], [[X-ray]], or electron-beam irradiation of clear quartz ([[rock crystal]]), which has been first doped with ferric impurities. Exposure to heat partially cancels the irradiation effects and amethyst generally becomes yellow or even green. Much of the [[citrine quartz|citrine]], [[Cairngorm (mineral)|cairngorm]], or yellow quartz of jewelry is said to be merely "burnt amethyst".<ref name=EB1911/><ref>
{{cite book
 |author =Michael O'Donoghue
 |title=Synthetic, Imitation, and Treated Gemstones
 |url=https://books.google.com/books?id=Jm3FwBiHaI4C&pg=PA124
 |year=1997
 |publisher=Taylor & Francis
 |isbn=978-0-7506-3173-0
 |pages=124–125
}}
</ref>