gemstones / Emerald

The name Esmeralda refers to Beryl green tonality considered very beautiful.
However, not all gem-quality green beryls are called emerald: indeed, if the hue is yellow green, we speak of Heliodoro; On the other hand, if it has a faint bluish green or a soft greenish color, it is aquamarine.

The most used form of carving is the rectangular Rome in table and steps, to the point that receives the epithet of carving in emerald.

The stones of beautiful color and weighing more than 2 carats have one of the highest values ;in the field of gems; They can equal and even exceed the price of the diamond. However, its quotation and decreases fairly quickly in the cases in which the tone is not typical, because it is too intense or too thin in excess

Clarity
Clarity is important, but more inclusions in the emerald are tolerated than in virtually any other gem. Unlike other beryl gems, emeralds usually contain rutile inclusions or other defects. These defects are not seen as negative aspects for the emerald as they would be for other gemstones. In fact, these failures are considered part of the character of the stone and are used to ensure the buyer a natural stone. In any case, the best quality inclusions are weak and not visible to the naked eye

Common treatments of the emerald
Oil is a common treatment for emerald. This term refers to the practice of immersing emeralds in a colorless oil or resin. It is often done using a vacuum chamber to aid penetration.
Gemology of the emerald

Species: Beryl
Color: emerald green, green, slightly yellowish green
Chemical composition: Aluminum Al2Be3Si6O18, beryllium silicate
Crystal system: (hexagonal), hexagonal prisms
Hardness: 7.5-8 (Mohs scale)
Specific gravity: 2.67 - 2.78
Refractive index: 1,565 - 1,602
Birrefringency: -0.006
Stripe color: White
Absorption spectrum: 683, 681, 662, 646, 637, 606, 594, 630-580, 477, 472
Fluorescence: Usually, none

Origins
Colombia is the world center of emerald mining. The Muzo mine, northwest of Bogotá, produces fine quality stones of a deep green color. The Chivor mine, northeast of Bogotá, is another important deposit, other places promising successful additional mining results.
Brazil has several deposits in Bahia, Goiás and Minas Gerais. The stones are lighter than the Colombian ones, mostly yellow-green and are often free of inclusions.
Further deposits are in Afghanistan, Australia (New South Wales, Western Australia), the Philippines, Ghana, India, Madagascar, Malawi, Mozambique, Namibia, Nigeria, Pakistan, Tanzania, Zambia and the United States (North Carolina).