It is a common practice in the trade that virtually all emeralds have been fracture filled by oil, resin or other substances to enhance their clarity, sometimes to enrich their color, or even durability. The geological conditions where emerald grows just make it very rare for emerald to be eye-clean. Therefore, emerald is classified as Type 3 according to the GIA colored stone grading system.
Whatever the substance is to fill emerald's fractures, they want to use the one that has the refractive index (RI) closest to that of emerald possible, so the substance can blend well in the emerald's interior and doesn't make a big difference when light strikes through it. They also prefer the substance that is able to remove and refill it in the future. Cedarwood oil with high-viscosity is one of the favorable fillers for emerald.
There have to be surface-reaching fractures in emerald in order to accept fillers. Gemologists often look for blue or yellow flashes in emerald under the microscope, or chalky colors under UV lighting to tell if that emerald is clarity enhanced. If it is, it must be noted in the report. Sometimes, it requires more sophisticated technology to spot fillers in an emerald. If that is the case, sending that emerald to GIA laboratory is recommended.
Clearly, if all other factors being equal, an eye-clean emerald commands the top price and is highly sought-after. The intensity of clarity enhancement in an emerald will affect its clarity grading; hence affecting its price per carat. GIA will record the indications of clarity enhancement in their reports, and classify them as minor (F1), moderate (F2), and significant (F3).
Many other factors will come into play when valuing emerald. If color is the most important factor, clarity is the second, cut and carat weight are to be followed. Origin is also a factor that could change emerald value significantly. Emerald can range from $20.00 to hundreds of thousands of dollars a carat. You would want to hire a professional to appraise your emerald or give you some advice before you invest your money in emerald.
Because most emerald is fracture filled, it is susceptible to heat and chemicals from the jewelry torch, ultrasonic jewelry cleaner, steamer etc. Emerald is also not recommended to set on daily-wear jewelry such as engagement rings. The daily activities and the interaction with household chemicals can do a huge damage on fracture-filled emeralds.
Now let's look at these admiring natural emeralds:
The photo bellow is an emerald crystal that exhibit its perfect six-sided hexagon crystal habit. A magnificent specimen like this one is usually displayed in the museum or in the collectors’ possession rather than being cut and faceted for the jewelry industry.
Photo courtesy: Artfixdaily
And this is an 18 karat yellow gold three stone cocktail ring featuring a 10 carat emerald GIA graded as Zambian in origin. You can already see their fractures visible to the unaided eye. However, its asking price is still $39,500 US. Thanks to the ring's custom design, the center stone's sought-after vivid bluish green color, its big size and origin!
Photo courtesy: 1stdibs
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You should have your emerald appraised at a trusted appraisal firm such as La Jolla Gem Appraisal. We will examine, identify and grade your emerald. After that we will conduct analysis and research to the extent that we could provide a credible opinion of its value (Notes: there are different types of value for different appraisals). You will receive a comprehensive appraisal report including a literal description of your loose emerald or mounted emerald jewelry, and the appropriate value for it. Appraisal fee is based upon an hourly rate. You can book an appointment with us here.
Trang Pham (Jen), GIA GG
GIA Graduate Gemologist
Accredited Senior Gemologist, AGA
La Jolla Gem Appraisal
7703 Fay Ave, La Jolla, CA 92037