Чем отличаются изумруды из разных месторождений?
There are two main types of emerald deposits - greisen and hydrothermal, which differ in the type of enclosing rocks and accordingly the conditions of crystallization of beryl and its varieties (including emeralds).
The main world centers for the emeralds mining today are Colombia (about 60% of the market), Zambia and Brazil. Smaller deposits of emerald raw materials are also found in Zimbabwe, Madagascar, Mozambique, South Africa, China, India, Afghanistan, Kazakhstan and Central Asia.
Emeralds of different genesis are characterized by certain features that allow the expert-gemologist to qualify them by the type of deposit.
One of such signs is the color of the emerald, which can indicate the origin of the stone indirectly. So Colombian emeralds are characterized by a bright green color with blue hues, emeralds of Zambia often show blue tones, and Uralic samples are distinguished by the presence of yellow shades in the color range of emeralds.
However, color is not an absolute criterion for definition the genesis of emeralds. A more accurate classification of this stones type by their origin occurs by using a complex of spectral diagnostic methods.
Another visual distinctive property is the specific form of multiphase inclusions and its composition. For example, emeralds from Afghanistan and Colombia have a similar distinctive "saw-like" form of polyphase inclusions, but differ in the composition of solid phases. There are microinclusions of quartz and siderite in emeralds from Afghanistan, and calcite and dolomite in Colombian emeralds.