Well I may be late in this reply and info but here goes anyway.
Most “lemon quartz” or “lemon citrine” seen on the market today is
treated by irradiation. In the last 5 or 6 years a lot of this
material has come out of Brazil and hit the US market. It is natural
material, either clear or smoky when mined and then irradiated to
achieve its yellow to yellow green color. Years ago I saw some
similar yellow quartz from the Ukraine that may have been natural,
but today the bulk of it is treated with irradiation.
Prior to the introduction of this material citrine was generally
recognized as the light golden to golden-orange and even red-brown
variety of quartz. This range of coloration is very different than
the “lemon yellow” in that it is not irradiated by man. Much of this
golden coloration range in citrine is derived from heat treated
amethyst. It is a low temp treatment somewhere in the 350-500 degree
C - nothing high tech. (As opposed to sapphire heat treatment which
is high tech and high temps 1200+ C. Temperatures only reachable
with sophisticated equipment.)
The lighter (straw color) to medium honey golden color is sometimes
mined as is with no heat treatment necessary. (I have Mozambique
citrine which is 100% natural, not treated.) The best citrine
colors come from southern Brazil and Uruguay areas and are created
by heating amethyst found in those localities.
I hope this helps clear up some confusion about citrine.
Stop by and visit us at the 2003 Tucson gem shows. My wife Marcia,
and I will be at the GJX (Gem and Jewelery Exchange) show booth #
700, February 6th thru 11th… I think. Near the bathrooms.
Best wishes and happy Thanksgiving, Steve Green
Rough and Ready Gems
Fine briolettes in over 50 gem materials, ultrasonic drilling and tall