Gemstone value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone. Heat can improve gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating is a common practice. Most citrine is made by heating amethyst, and partial heating with a strong gradient results in “ametrine” – a stone partly amethyst and partly citrine. Aquamarine is often heated to remove yellow tones, or
Carlin stone the circle were found a small perforated axe-hammer, portions of 3 bronze armlets, flint chips and a jet button. This natural stone outcrop is known as Carlin Maggie and has the look of something imported from Easter Island, but it is natural. It is said to be a witch turned to stone by the Devil after she got on his nerves ("carline" is an old Scots word for 'witch'). The Devil threw a lightning bolt which had the effect of petrifying her. It is a rock pillar estimated to be high, on the Western slope of Bishop Hill, overlooking Loch