GemSelect is a leading online dealer in fine gemstones, specializing in sapphire, spinel, tourmaline, peridot, topaz and zircon. Demantoid Garnet
In the gemstone world we have a number of technical terms we use to describe the luster of a gemstone. These terms include metallic, adamantine, pearly, silky, vitreous, resinous, and waxy. The term adamantine means 'like diamond' and is used to refer to gemstones which have especially high brilliance and intensive dispersion or fire.
There are very few gemstones that have a luster that deserves to be called adamantine. Diamond is one, of course; the rare demantoid garnet is another. But one of the members of this exclusive group is a gem that few people have heard of, and even fewer have seen: sphene.
Sphene is a calcium titanium silicate that is also known by its mineralogical name, titanite. The name sphene comes from the fact that its crystals are typically sphenoid (from the Greek sphenos meaning wedge). The name titanite comes, not surprisingly, from its titanium content.
Sphene occurs as translucent to transparent, reddish brown, gray, yellow, green, or red monoclinic crystals. Sphene has an unusually high refractive index (1.843-2.110), higher than zircon, ruby and sapphire. But it is sphene's dispersion or fire which is truly exceptional, exceeding even that of diamond.
When you hold a gemstone and turn it in the light, some gems will display flashes of color, which is the result of the dispersion of white light into the colors of the spectrum. Dispersion occurs when different wavelengths of light are refracted by a different amount by the refracting medium. Diamond is famed for this quality, but sphene actually has a higher dispersion value than diamond. This is why high quality sphene usually looks multicolored in photographs.
In addition to its exceptional fire, sphene is itself strongly pleochroic, meaning it displays more than one color. Sphene typically displays least three colors (colorless, greenish-yellow, reddish) when looked at from different angles. Sphene is usually found with some inclusions and the rare clean pieces are highly sought after.
Sphene has traditionally been rare and sought after mainly by collectors. Recently the supply has improved with new material from Sri Lanka and Madagascar, and sphene is now being used for jewelry. However, sphene is diamond-like only in some respects. It is a fairly soft stone -- 5 to 5.5 on the Mohs hardness scale -- about the same hardness as apatite, chrome diopside, turquoise and lapis lazuli. So sphene is not suitable as a ring stone for everyday wear. But it makes outstanding pendants and earrings.
- Related Articles
- Related Q&A
creative jewelry gifts
By: sarah | 01/12/2009All women are fond of jewelry and are always hungry for jewels. If they like jewelry they will do each and every thing to get it .I am 21 years old female and I am always interested in creative gifts. I will reveal my experience that how I discovered my creative gifts for my sisters birthday. She has just turned 18 and just like me she is also interested in creative gifts.
Recipe for jewelry gifts
By: sarah | 01/12/2009Relation ships are not built in one day it takes heart and Soule to make a relationship .a true relation ship is far stronger then anything on the whole planet formed with great love and care. Creative jewelry can symbolize your relationship with a particular person and defines the importance of that person in your life. Giving creative jewelry as a gift shows the great care and love for that person. Creative Jewelry gifts will improve your relationship with a person that is very close to you.
Smart Tips For a Memorable Christmas Gift
By: Angara.com | 01/12/2009One of the good ways to buy memorable Christmas gifts, without bloating your budget is through planning and prioritizing.
Charms, charms they're everywhere!
By: Trade Your Charms | 01/12/2009Charm bracelets are making a return to fashion. Thanks to new designers we now have a new type of charms that can be threaded onto a solid chain. Pandora are leading the way with marketing but hot on its heels are Chamilia, Biagi, Trollbeads and Lovelinks to name a few.
Sell Gold and Feel Wealthier
By: Harry Smith | 01/12/2009You all know the feeling when you come upon some unexpected cash. This is the emotion you get when you sell gold. You get a hassle-free transaction when you use our services because no company understands the people who sell gold like we do.
Scrap Gold Cash can be an Unexpected Source of Money
By: Harry Smith | 01/12/2009Scrap gold can include gold coins, but scrap gold is anything with retrievable gold content. This includes gold fillings (do not take them out to sell them), broken watches and jewelry that would cost more to repair than selling and receiving scrap gold cash.
Money4Gold & Anthony Sullivan Take the Worry Out of Selling Gold Jewellery
By: Harry Smith | 01/12/2009If this is your first adventure with selling jewellery to an online company, you might be a little wary or worried; granted, it can be a bit of an anxious experience, especially if you’ve never done so before.
Money 4 Gold UK is the Best in the Industry
By: Harry Smith | 01/12/2009The economy of the UK is not yet recovered fully and could collapse back into a W shaped recession, meaning after a time of economic recovery, another downturn caused by a variety of reasons can result.
Ancient Turquoise Gemstones
By: GemSelect | 17/06/2009 | JewelryFor many Americans, turquoise seems a distinctively American gemstone -- mined in Arizona, New Mexico, Colorado and Nevada, and with a long history in native American jewelry. But turquoise has been an important gemstone in many eastern cultures for thousands of years.
Lapis Lazuli from Afghanistan
By: GemSelect | 17/06/2009 | JewelryThere are few gemstones with as long and romantic a history as lapis lazuli. Though found in several locations around the world, the finest lapis comes from the Badakhshan province of northern Afghanistan, where it has been mined continuously for over 6,000 years.
Star Sapphire Gemstones
By: GemSelect | 17/06/2009 | JewelryAsterism or the star effect is an example of an optical effect found very rarely in a small number of gem types cut as cabochons. The most famous examples are star sapphire and star ruby. But asterism may also be exhibited by moonstone, quartz, spinel, citrine, diopside, emerald, garnet and chrysoberyl.
Chrome Diopside Gems
By: GemSelect | 17/06/2009 | JewelryFine green gemstones are rare and expensive. At one time, emerald was the only choice. Then tsavorite garnet came on the market in the 1970's, followed by chrome tourmaline. Both soon became as rare and expensive as emerald. But the situation began to change with the introduction of chrome diopside in 1989.
Tanzanite Prices
By: GemSelect | 17/06/2009 | JewelryTanzanite, a rare violet-blue form of the mineral zoisite, was first discovered in 1967 in Tanzania. East Africa remains the only source for tanzanite and the supply is extremely limited. The limited supply, combined with soaring demand, has resulting in rising prices. Is Tanzanite worth it?
Natural Sphene: More Fire than Diamond
By: GemSelect | 15/06/2009 | JewelryWhen you hold a gemstone and turn it in the light, some gems will display flashes of color, which is the result of the dispersion of white light into the colors of the spectrum. Diamond is famed for this quality, but the gemstone known as sphene actually has a higher dispersion value than diamond. This is why high quality sphene typically looks multicolored in photographs.
History of Peridot Gemstones
By: GemSelect | 15/06/2009 | JewelryPeridot is a gemstone with a fascinating history, both in nature and culture. It is one of the oldest known gemstones, with ancient written records documenting the mining of peridot as early as 1500 B.C. It is a gem especially connected with ancient Egypt, and some historians believe that the famous emeralds of Cleopatra were actually peridots.
Pink Kunzite Gemstones
By: GemSelect | 15/06/2009 | JewelryKunzite is still unknown to many gemstone buyers. But the gemstone world began to pay attention to kunzite when they learned of a 47 carat kunzite ring that President John F. Kennedy had purchased for his wife, Jacqueline. He never had the chance to give her the ring before his tragic death in 1963. The kunzite ring sold for more than $410,000 at a Sotheby's auction of the Estate of Jacqueline Kennedy Onassis in 1996.