MAIN STONE AMETRINE

WEIGHT..17.65 Carats

DIMENSION...18.0 X 13.0 X 11.0mm

STONE SHAPE...OVAL

STONE COLOUR ...TOP BI-COLORS PURPLE - YELLOW

CLARITY/GRADE..IF

LUSTER.. RAVISHING

TREATMENT..UNHEATED

ORIGIN.. BOLIVIA, SOUTH AMERICA

WEIGHT... is approx 4 grams

What is Ametrine?

Most people have never heard of ametrine and are very surprised to see purple and yellow in a single transparent gemstone.

Ametrine is a rare gemstone with a finite supply that is produced at only one mine in the world. It is a relative newcomer to the gemstone trade, being available in small quantities for just a few decades.

Ametrine is a variety of bicolor quartz that has zones of amethyst (purple) and citrine (golden yellow) in contact with one another in a single crystal. The words AMEthyst and ciTRINE were combined to yield the name "ametrine," which is widely used in the gemstone trade. This material is known by other less-frequently used names including: "amethyst-citrine," "trystine," "bicolor amethyst," "bicolour quartz," and "bolivianite." The bolivianite name is a response to the material being designated as the national gemstone of Bolivia.

History of Ametrine

According to legend, the Ayoreo Indian tribe of eastern Bolivia knew about the bicolour quartz crystals over 500 years ago. Perhaps the earliest formal documentation of natural quartz crystals with zonal colouring of purple and yellow is in a 1925 issue of American Mineralogist. These were basal sections of quartz crystals with colour sectors alternating between purple and yellow.

Reports of a quartz gemstone of mixed purple and yellow colour being produced anywhere in the world begin in the 1960s from vague localities in Brazil, Bolivia, and Uruguay. Because the material was not attributed to a specific mine, some people believed it was produced synthetically, produced by treating amethyst, or mined illicitly.

In 1989, changes to Bolivian mining laws allowed gemstone mining in eastern Bolivia, and a company, Minerales y Metales del Oriente S.R.L., obtained exclusive mining rights to a few thousand acres. Their property included a mine location with evidence of a long history of illicit mining. To establish credibility in the gemstone trade, the company invited geologists and gemologists to the mine and allowed them to confirm for themselves that the ametrine and citrine produced there were natural.

Today, their Anahi Mine is the world's only important commercial source of natural ametrine and anahite (a clear variety of quartz with a very light tint of lilac). The mine also produces amethyst, citrine, and bicolour materials that are a combination of amethyst and clear quartz (bicolour amethyst) or citrine and clear quartz (bicolour citrine).