Ametrine is a variety of quartz
that contains both amethyst and
citrine
sectors in the same crystal. Both amethyst and citrine are colored by
small
amounts of iron Amethyst color develops when
iron-containing
quartz is exposed to ionizing radiation. In nature, gamma rays from the
decay of potassium-40 are the most likely source of ionizing
radiation. The only significant source of natural
ametrine is
the Anahí mine, in eastern Bolivia. The mine is operated by
Minerales
y Metales del Oriente, S.R.L., Santa Cruz, Bolivia, and employs about
70
workers at the mine site. It is the source of all the natural ametrine
currently on the world's market. In the early days of production, there
was much mis-information about the locality with Brazil and Uruguay
frequently
being mentioned as the source of ametrine. As is the case
for
all amethyst, the amethyst color center in ametrine is somewhat
photosensitive
and will be lost upon prolonged exposure to bright light.
Ametrine
is an excellent gemstone for jewelry.
It is very durable and
rated
at 7 on the mohs scale of hardness. Loose ametrine gemstones can be viewed
here.
