Although jewelers might expect amethyst from Siberia or Zambia to have better color than amethyst from Brazil, origin alone does not add value to amethyst. Value is based on quality, and color is the most important value factor regardless of country of origin.
In general, turquoise with a robin’s egg blue color is preferred. Unusual colors like yellow-green and pure green are in demand for use in inlay jewelry.
You should assume your ruby is heated. Rubies that have a report that confirms there is no evidence of heat from an independent laboratory like NQTC command a premium due to their rarity. Rubies that have been diffused or that are glass filled are worth less than heated rubies.
Not all Russian demantoids have these famous chrysotile inclusions. Horsetails are also seen in demantoids from Iran and Italy but not in those from Namibia or Madagascar.
Most biologists agree the Jurassic Park scenario isn’t possible, as any blood an insect was carrying would deteriorate rapidly and be contaminated with the insect’s DNA. However, scientists have extracted DNA from insects in 120-million-year-old amber.
Yes. The NQTC Colored Stone Identification Report or Colored Stone Identification & Origin Report will confirm whether or not an emerald has been treated.
Buyers must be aware of a common imitation. Called goldstone, it’s made of glass that contains small, flat copper crystals.
Every mine produces a wide range of quality. For gems of exceptional quality, an independent determination of origin adds to value. For sapphire, Kashmir receives the highest premium, although Myanmar (Burma), Sri Lanka and Madagascar also produce top-quality gems.
Emerald value can range from a few dollars to tens or even hundreds of thousands of dollars per carat, depending on quality.
Although it’s always interesting to know where a gem was mined, origin isn’t an important factor in an aquamarine’s value. Famous mines are well regarded because they produce fine-quality gems that are valuable; gems aren’t fine or valuable just because they come from famous mines.