Sapphire, with its hardness of 9 on Mohs hardness, is second only to diamond, which renders it one of the most valuable and wearable gemstones of all-time. Sapphire is a 'precious four' gem and offers superb brilliance and rich, vibrant colors. Although most sapphire is heated or enhanced in other ways to improve color, clarity and stability, unheated and completely untreated natural sapphire can still be found. Usually unheated sapphire gems are found only in small sizes, but occasionally, large, clean stones are uncovered too. Because unheated sapphire is such a rarity, they are indeed relatively expensive, particularly unheated top-color blue 'Ceylon' sapphire. Unheated, natural sapphire is mostly sourced from Africa, though Australia and parts of Asia are known to produce some fine materials too.
As of recent times, Madagascar and Tanzania are two of the most important sources for fine untreated, unheated sapphire, as is Thailand. Tanzanian sapphire is usually pink to violet in color (often violet-blue), and many of the specimens exhibit very noticeable color change properties. Color-change unheated sapphire can be very expensive and is highly sought-after by both jewelers and gem collectors. Fine quality unheated sapphire gems from Madagascar, as well as Australia, display silk inclusions, which are highly desirable. The silky appearance is cause by rutile inclusions and the presence of such silk is usually a good indicator that the gem has not been heated, since rutile inclusions melt at a much lower temperatures than those at which sapphire is heated. Sapphire is also the official birthstone for those born in the month of September.
Gesamtbewertung -> 10
The Ruby Zoisite bird is beautiful and will delight my sister, I hope, for her birthday in July. I, personally love the stone which is within her ruby birthday stone, and the bird appears beautifully carved.
I would recommend gem select. They care about all details from description to quality to packaging to shipping. I specialize in turquoise so I would like more explicit provenance than "American"... Couldn't they give me mine or at least state? Never the less very classy. Also, their turquoise cabochons are very thick for good and bad. I cut many in half to make them more versatile and commercially useful. If one can't do that then you are going to have to settle for wire wrapped jewelry. I think that overall thy are a great resource.
I am looking forward to my purchased opal to be set in a ring and a necklace for my sister for her birthday present I am interested I working with this company in the future if we are happy with our opals thanks so much for your communication