Turkmenistan Emerald Diamond White Gold Engagement Ring 194

Turkmenistan Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

A gem graded none on the enhancement scale may still exhibit visible inclusions. Laboratories tend to apply these criteria differently. Some gem labs consider the mere presence of oil or polymers to constitute enhancement. 

Turkey Emerald Diamond White Gold Engagement Ring 193

Turkey Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

 Other treatments, for example the use of green-tinted oil, are not acceptable in the trade. Gems are graded on a four-step scale; none, minor, moderate and highly enhanced. Note that these categories reflect levels of enhancement, not clarity. 

Tunisia Emerald Diamond White Gold Engagement Ring 192

Tunisia Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir

The U.S. Federal Trade Commission requires the disclosure of this treatment when an oil treated emerald is sold. The use of oil is traditional and largely accepted by the gem trade, although oil treated emeralds are worth much less than un-treated emeralds of similar quality.

Trinidad and Tobago Emerald Diamond White Gold Engagement Ring 191

Trinidad and Tobago Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

Other liquids, including synthetic oils and polymers with refractive indexes close to that of emerald such as Opticon, are also used. These treatments are typically applied in a vacuum chamber under mild heat, to open the pores of the stone and allow the fracture-filling agent to be absorbed more effectively

Tonga Emerald Diamond White Gold Engagement Ring.190

]Tonga Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

Most emeralds are oiled as part of the post-lapidary process, in order to fill in surface-reaching cracks, improving their clarity and stability. Cedar oil, having a similar refractive index, is often used in this generally accepted practice. 

Tokelau Emerald Diamond White Gold Engagement Ring 189

Tokelau Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut into cabochons, rather than faceted shapes. Faceted Emeralds are most commonly given the Oval cut, or the signature Emerald cut, a rectangular cut with facets around the top edge.

Togo Emerald Diamond White Gold Engagement Ring.187

 Togo Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

Eye-clean stones of a vivid primary green hue (as described above) with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone command the highest prices.

Timor-Leste (East Timor) Emerald Diamond White Gold Engagement Ring.186

Timor-Leste (East Timor) Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

The inclusions and fissures within an emerald are sometime described as "Jardin" (French for 'garden'), because of their mossy appearance.[12] These imperfections within the stone are unique to each emerald and can be used to identify a particular stone. 

Tibet Emerald Diamond White Gold Engagement Ring.185

Tibet Emerald Diamond White Gold Engagement Ring.

  By Farzana Aamir 

Thus, if an emerald has no visible inclusions to the eye (assuming normal visual acuity) it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated ("oiled", see below) to enhance the apparent clarity. 

Thailand Emerald Diamond White Gold Engagement Ring.184

Thailand Emerald Diamond White Gold Engagement Ring.   

By Farzana Aamir 

Brazilian emerald (grass-green variety of the mineral beryl) in a quartz-pegmatite matrix with typical hexagonal, prismatic crystals.

Emerald tends to have numerous inclusions and surface breaking fissures. Unlike diamond, where the loupe standard, i.e. 10× magnification, is used to grade clarity, emerald is graded by eye. 

Tajikistan Emerald Diamond White Gold Engagement Ring 183

Tajikistan Emerald Diamond White Gold Engagement Ring.  

By Farzana Aamir 

In addition, a fine stone should be well saturated; the hue of an emerald should be bright (vivid). Gray is the normal saturation modifier or mask found in emerald; a grayish-green hue is a dull green hue

Taiwan (Republic of China) Emerald Diamond White Gold Engagement Ring 182

 Taiwan (Republic of China) Emerald Diamond White Gold Engagement Ring.

  By Aamir Mannan Shaikh.

Only gems that are medium to dark in tone are considered emerald; light-toned gems are known instead by the species name green beryl. The finest emerald are approximately 75% tone on a scale where 0% tone would be colorless and 100% would be opaque black. 

Syria, Syrian Arab Republic Emerald Diamond White Gold Engagement Ring 181

Syria, Syrian Arab Republic Emerald Diamond White Gold Engagement Ring 

 By Aamir Mannan Shaikh.

In gemology, color is divided into three components: hue, saturation and tone.[8] Emeralds occur in hues ranging from yellow-green to blue-green, with the primary hue necessarily being green. Yellow and blue are the normal secondary hues found in emeralds. 

Switzerland Emerald Diamond White Gold Engagement Ring 180

Switzerland Emerald Diamond White Gold Engagement Ring 

By Aamir Mannan Shaikh. 

In America, the distinction between traditional emeralds and the new vanadium kind is often reflected in the use of terms such as "Colombian Emerald"

Sweden Emerald Diamond White Gold Engagement Ring 179

Sweden Emerald Diamond White Gold Engagement Ring 

By Aamir Mannan Shaikh. 

In the 1960s, the American jewelry industry changed the definition of "emerald" to include the green vanadium-bearing beryl as emerald. As a result, vanadium emeralds purchased as emeralds in the United States are not recognized as such in the UK and Europe. 

Sudan Emerald Diamond White Gold Engagement Ring 176

Sudan Emerald Diamond White Gold Engagement Ring.

 By Aamir Mannan Shaikh.

Cut emeralds

Emeralds, like all colored gemstones, are graded using four basic parameters–the four Cs of Connoisseurship: Color, Cut, Clarity and Carat weight. Before the 20th century, jewelers used the term water, as in "a gem of the finest water",

Emerald Beautiful Engagement Ring 29

Emerald Beautiful Ring.
By Aamir Mannan.

In some minerals the figures very somewhat; thus in zircon, while the blue, white, and golden 'fried' type most popular in moderan jewellery are almost constant in their birefringence of 0.059. many of the ceyclonese zircons. particularly the green varieties, have a much lower double 

refractions, sinking in some cases practically to zero. this peculiaity is unique amongst minerals, and will be discussed at greater length in the chapter on zircon. synthetic rutile has been manufactured in the USA (since 1949), and its anormous double refraction will be one means of identification. calcite, though not a gemstone, plays an important part in gemmological instruments in its optocally pure form of 'ice land spar', how, apart