Quartz Species Part 3 Citrine and Prasiolite

Hi everyone,

Here we are again on our journey through the wonderful world of the quartz family.  I am learning so much from the books and websites that I have looked at and visited.  I find that the quartz family or species is very interesting as there are so many colours and varieties to this family.  I hope that you will learn something new and interesting in this blog today.  I find that I always do.  I hope you have fun.

So let's talk citrine and Prasiolite.  I would like to start with citrine first.  I also would like to mention that the information that I used to write this blog has come from the book Gemstones of the World by Walter Schumann.  Citrine has the colour range of light yellow to dark yellow, gold brown and the colour streak is white.  The Mohs hardness is 7 and the density is 2.65.  There is no cleavage and the crystal system is hexagonal, trigonal.  The chemical composition is silicon dioxide and the transparency is transparent.

Citrines name is derived from the lemon yellow colour of the gemstone.  The colour agent for citrine is iron.  According to Mr. Schumann natural citrines are very rare.  Most of the citrines found on the market today are heat-treated amethysts or smoky quartz.  Brazilian amethysts are heated at 878 degrees F to produce a light yellow colour.  To achieve a dark yellow or red-brown colour the amethyst has to be heated to 1022-1040 degrees F.  To make a smoky quartz a citrine colour the gemstone must be heated to 390 degrees F.  To tell if a citrine has been heated treated look at the colour.  If it has a reddish tint to it, it has been treated.  If the gemstone is light yellow in colour than it is most likely a natural citrine.  There used to be names that were used to describe citrine but are no longer acceptable.  These names are Bahia, Madeira and Rio Grande topaz.  The only acceptable use is when they use it to describe the colour.  An example of this would be Madeira Citrine colour.  Citrines are usually found in Brazil, Madagascar, the United States, Argentina, Burma, Namibia, Russia, Scotland and Spain.

Prasiolite's colour is leek green and the colour streak is white.  The Mohs hardness is 7 and the density 2.65.  There is no cleavage and the crystal system is hexagonal, trigonal.  The chemical composition is silicon dioxide and the transparency is transparent.  The name prasiolite is Greek for leek green stone.  It is not a naturally found gemstone.  Prasiolite is created by heating violet amethyst or yellowish quartz from the deposit Montezuma in Minas Gerais, Brazil to a temperature of around 930 degrees F.

I hope that everyone that reads this blog today has had a fun time and learned something new in regards to citrine and prasiolite.  I enjoy writing about new gemstones and learning about new gemstones.  Please drop me a line and let me know how I am doing.  I would love to hear from you out there.  Until next time.

The rare gem lady