Ametrine, also known as trystine or by its trade name as bolivianite, is a naturally occurring variety of

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

. It is a mixture of

amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος ''amethystos'' from α- ''a-'', "not" and μεθύσκω (Ancient Greek) / μεθώ (Modern Greek), "intoxicate", a reference to the belief that ...

and citrine with zones of purple and yellow or orange. Almost all commercially available ametrine is mined in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

. The colour of the zones visible within ametrine are due to differing

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

s of

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

within the

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

. The citrine segments have oxidized iron while the amethyst segments are unoxidized. The different oxidation states occur due to there being a

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

gradient across the crystal during its formation. Artificial ametrine is grown with the hydrothermal method using solutions doped with specific elements, followed by irradiation of the created crystals. Ametrine in the low price segment may stem from synthetic material. Green-yellow or golden-blue ametrine does not exist naturally.

Structure

Ametrine is composed of

silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

(SiO₂) and it is a tectosilicate, which means it has a silicate framework linked together through shared oxygen atoms.

History

Legend has it that ametrine was first introduced to

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

by a conquistador's gifts to the

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

Queen in the 1600s, after he received a mine in

as a

dowry A dowry is a payment, such as property or money, paid by the bride's family to the groom or his family at the time of marriage. Dowry contrasts with the related concepts of bride price and dower. While bride price or bride service is a payment ...

when he married a princess from the native Ayoreos tribe.Vasconcelos, Paolo; Wenk, Hanz-Rudolf; Rossman, George. "The Anahí Ametrine Mine, Bolivia," Gems and Gemology, Spring 1994, p. 4-23

References

External links

Ametrine at the International Colored Gemstone AssociationAmetrine: Ametrine mineral information and dataInsider Gemologist: What Are the Identifying Characteristics of Citrine, Ametrine, Smoky Quartz, and Scapolite?
{{Silica minerals Quartz gemstones

Structure

History

See also

References

External links