Lush green emeralds have been valued since prehistoric times as the most precious of gemstones. Hildegard von Bingen (1098-1179) reflected on the healing powers of emeralds in her famous Physika, “ The emerald grows in the early morning at sunrise, when the green power of the earth and its plants have especially strong and vital energy, since the air is still cold and the sun is already warm …And so the emerald is effective against all weaknesses and sicknesses of mankind, because the sun procures it and because its whole substance comes from the green energy of the air.”
The most important influence on an Emerald’s value is its colour. The highest priced emeralds are those with intense, vivid colour saturation in hues of green to bluish green. Emerald value is also based in tone – lightness and darkness. Even if it has high saturation, an emerald’s value is lowered if it is too dark. Emeralds of equal weight but different colour saturations, do not cost the same. Emeralds are pleophoric, meaning they display different colours in different directions. The colors can be so similar that you usually need special equipment to tell one colour from another. A fine emerald is rare, and often demands a higher price then a diamond with equal clarity.
DURABILITY, TREATMENT AND CARE
Emeralds should be handled with care. When choosing settings for your emeralds, consider how you will be wearing or using your gems since emeralds are less tough than some other stones (about 7-8 on the Mohs hardness scale). It is common trade knowledge that most natural emeralds are treated. Most emeralds are treated with oil, opticon or other polymer resin to improve their apparent clarity. Warm, soapy water is safe for cleaning.