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Fine Jewelry University Articles matching: “Black sapphire”
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Fine Jewelry University (Show All FJU Articles)
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What to Do When Your Ring Irritates Your Skin
… which can begin hours or even days after contact and may last for several weeks. Some people’s skin even turns black or green when they wear certain jewelry. One of the most common metal allergies is Nickel which is added to pure gold in … a simple discoloration on top of the skin from the metal. Also, tarnish from silver jewelry can rub off and leave a blackish residue. In both cases, the color will easily wipe or wash off. You can avoid this type of discoloration simply …
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Gem in the Spotlight: Aquamarine
… in shades of blue-green. Aquamarine has a refractive index of 1.577 to 1.583 and is doubly refractive. Aquamarine’s specific gravity is 2.72 and it has a Mohs hardness of 7.5-8.0. For comparison, this means that it is softer than Sapphire, harder than Quartz, and similar to Topaz. This makes it a very durable stone that is suitable for regular wear. But, care should still be taken to ensure that the stone is not damaged. Caring For and Cleaning Aquamarine To maintain the …
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Gem in the Spotlight: Topaz
… preference. Topaz itself is a hard gemstone with a Mohs hardness of 8. Mohs hardness is a standardized metric of how difficult it is to scratch something. For reference, topaz is a bit softer than diamond which is a 10 and corundum (sapphire/ruby) which is a 9 on the scale. It is a bit harder than emerald at 7.5-8 and quartz which comes in at 7. Here are some more gemological stats for reference: Refractive index: 1.619 to 1.627 Birefringence: 0.008 to 0.010 Specific …
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Gem in the Spotlight: Tanzanite
…, even with its rarity and dynamic look, tanzanite is still less in price than more commonly known gems like rubies, sapphires, and emeralds. Gemology of Tanzanite Gemologists refer to this gem as blue zoisite. The vast majority (current … its color. Tanzanite has a Moh’s hardness of 6-7, making it about the same hardness as quartz, softer than ruby, sapphire and emerald and hard than opal. Tanzanite has a refractive index of 1.69-1.70. History and Lore of Tanzanite Tanzanite …
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Gem in the Spotlight: Ruby
… arguably the richest history of all gemstones. Gemology of Ruby Rubies are in the corundum gem family along with sapphires. Corundum is an extremely durable form of aluminum oxide with a Moh’s hardness of 9. This makes ruby one of the … from trace amounts of chromium in the crystal structure. If they are too purple or too pink, they are called purple sapphires or pink sapphires, respectively. Since sapphires and rubies are the same gem material, they also share a refractive…
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The Magic of Polarized Light
…gemstones, due to their unique chemical structure, actually polarize light themselves. These gems are doubly refractive (DR) and they will split incoming light in multiple directions. Some common examples of doubly refractive gems are sapphire, tourmaline, and moissanite. These are contrasted with singly refractive (SR) gems like diamond that only bend light in one direction. Gemologists use the term birefringence to refer to how doubly refractive a particular gem is. By …
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Gem in the Spotlight: Amethyst
… found in smaller deposits in other countries such as Russia, the United States, and Canada. Amethyst is known for its durability with a Mohs hardness rating of 7. For reference, amethyst is roughly as hard as tourmaline, softer than sapphire and topaz, and harder than opal and tanzanite. This makes it a durable gemstone that is resistant to scratching and chipping. It is also resistant to heat and chemicals which means that it can withstand daily wear and tear. Amethyst …
