amethysts from certain localities change colour to green when heated
under appropriate condition. They are known as “prasiolite” or green
amethyst. A large amount of green quartz in a similar colour has been
on the gem market recently and are for sale quite cheaply. When
studied it was proved that they were not greened amethyst but actually
irradiation-treated quartz. Synthetic green quartz, although in small
quantity, is also available on the market. Identification of green
quartz is becoming more complicated today because of these factors.