Oval Spessartite
How to Buy Colored Gemstones by Size and Weight
Diamonds are typically bought and sold by carat weight. Since high quality diamonds are cut with standard proportions, you can buy a setting designed for a round brilliant diamond of a specific carat weight, such as 75 points or 1 carat. The diamond you buy will almost always fit the setting designed for that carat weight.
The colored gemstone business is quite different. Though rubies, sapphires and other colored gems are sold by carat weight, they really need to be purchased by size. It’s not possible to purchase a ring setting designed for a round 1.5 carat sapphire, because sappires with that weight can vary considerably in size. In addition, the ring mounting that will fit your 1.5 carat round sapphire is unlikely to fit a 1.5 carat round zircon or tourmaline. Settings for colored stones are always sold by size, rather than by carat weight.
The explanation for this difference has to do with two properties of colored stone — their density and their cut. The various gemstone materials vary by density, sometimes significantly. Density or specific gravity is measured as the ratio of the density of the gemstone to the density of water. It is expressed as a number which indicates how much heavier the gemstone is compared to an equal volume of water. A higher number indicates a higher density. Here are some density values for common gemstones:
Gemstone density varies by the chemical composition of the material. A number of popular colored gemstones are substanially denser than diamond, including all the garnets (such as spessartite, tsavorite, demantoid and rhodolite), corundum (ruby and sapphire), zircon and chrysoberyl. This means that a 1 carat spessartite garnet, for example, will be noticeably smaller in size than a 1 carat diamond. Buying a garnet or sapphire by carat weight often leads to disappointment when the gem appears smaller than expected. On the other hand, some colored stones have a lower density than diamond, including tanzanite, chrome diopside, kunzite, apatite, fluorite, jadeite, tourmaline, prehnite, beryls (emerald, aquamarine,morganite and yellow beryl), quartz (amethyst, ametrine, etc.) and opal.
Colored gemstone also tend to be cut quite differently from diamonds, with more weight in the bottom or pavilion of the gemstone in order to maximize color. This means that colored stones tend to “face up” smaller than a diamond of similar carat weight. For example, spinel is a gemstone with a density just slightly higher than diamond. But a 1 carat spinel will usually have a smaller face than a diamond of similar weight because of the heavier pavilion.
When these two considerations — density and cut — are combined, the size of some colored gems can be dramatically different than the buyer expects, especially if the buyer’s expererience is mainly with diamonds. In practical terms, this means one has to be very careful when buying a colored gem, especially a ruby, sapphire, garnet or zircon, for an existing setting. In this case it is crucial to know the exact size of the setting and select a gem by size, not by weight, to fit.
On the other hand, buying a lower density gem by carat weight can result in receiving a gem larger than one expected. This can be true for gems such as tourmaline, quartz, beryl, kunzite, moonstone and opal. By way of comparison, a 2 carat oval opal would have a typical size of 11 x 9 mm, while a 2 carat oval diamond would be only 9 x 7 mm, a difference of nearly 40%.
About the Author
AJS Gems, Bangkok is a leading online dealer in fine gemstones, including Burma ruby, sapphire, spinel, tourmaline and zircon. Buying Guide to Colored Gemstones
Precision Cut 2.53ct Spessartite Garnet Oval Shape
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3.55ct Genuine Mandarin Spessartite Garnet Oval Cut VVS $99.99 |
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3.45ct Genuine Mandarin Spessartite Garnet Oval Cut VS $86.25 |
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3.42ct Genuine Mandarin Spessartite Garnet Oval Cut VS $85.50 |
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3.84ct Genuine Mandarin Spessartite Garnet Oval Cut VVS $85.00 |
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3.22ct Genuine Mandarin Spessartite Garnet Oval Cut VVS $322.00 |
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3.13cts INTENSE Red SPESSARTITE GARNET Natural Faceted GEMSTONE VS OVAL $49.50 |
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3.60Ct.Natural Nice 7×9 Oval Red Spessartite Garnet Gem $29.99 |
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1.25 CT OVAL GLITTERING MANDARIN ORANGE SPESSARTITE !NR $7.00 |
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NATURAL OVAL RICH ORANGE NAMIBIA SPESSARTITE GARNET 1.23 CT.NR FREE COMBINE GEM $0.99 |
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THE BIG OVAL CUT REDISH ORANGE SPESSARTITE 21.82 CT $99.99 |
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Natural 1.95 Ct. Beautiful Gem Stone Oval Shape Orange Red Spessartite Garnet $14.65 |
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Natural Gem 1.51ct 7×6mm Oval Deep Orangish Red SPESSARTITE GARNET, NAMIBIA $0.99 |
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RAVISHING! OVAL 8×6mm. TOP ORANGE SPESSARTITE GARNET-CZ 925 SILVER RING SIZE 7.5 $16.99 |
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2.80ct Fabulous Oval Natural Fanta Orange Spessartite $99.00 |
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Natural Gem 2.59ct 7.5×6.5mm Oval Reddish Orange SPESSARTITE GARNET, NAMIBIA $11.20 |
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Natural Gem 1.42ct 7×5.5mm Oval Dark Orangish Red SPESSARTITE GARNET, NAMIBIA $0.99 |
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Natural Gem 6.89ct 12.5×9.5mm Oval Orangey Red SPESSARTITE GARNET, NAMIBIA $84.00 |
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4.90 ct. NATURAL GEM STONE OVAL CABOCHON for 12×10mm ORANGE SPESSARTITE GARNET $9.99 |
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Natural Gem 1.54ct 7×6mm Oval STUNNING Fanta Orange SPESSARTITE GARNET, NAMIBIA $1.75 |
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1.80 ct. EXCELLENT NATURAL GEMSTONE OVAL CUT ORANGE RED SPESSARTITE GARNET $9.99 |
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2.05CT.GLISTENING! OVAL FACET ORANGE NATURAL SPESSARTITE GARNET NAMIBIA $0.99 |
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4.29 CT AAA! NATURAL! RED AFRICA SPESSARTITE GARNET OVAL $7.06 |
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2.15 CT. GORGEOUS NATURAL GEMSTONE OVAL CUT ORANGE SPESSARTITE GARNET $9.99 |
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Natural Gem 2.18ct 8×6.5mm Oval Vibrant Orange SPESSARTITE GARNET, NAMIBIA $42.00 |
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Natural Gem 2.11ct 7.5×6mm Oval Deep Orangish Red SPESSARTITE GARNET, NAMIBIA $0.99 |
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1.22CT.GLORIOUS! OVAL FACET ORANGE & RED NATURAL SPESSARTITE GARNET NAMIBIA $0.99 |
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Genuine Natural GemStone Oval Cut Untreated Top Quality Fanta Orange Spessartite $14.99 |
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1.70 CT. SPLENDID NATURAL MINED GEMSTONE OVAL RICH ORANGE SPESSARTITE GARNET $24.99 |
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1.25 CT. NATURAL EARTH MINED GEM STONE OVAL CUT RICH ORANGE SPESSARTITE GARNET $14.99 |
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1.80ct INTENSE Red SPESSARTITE GARNET Natural Faceted GEMSTONE Oval CHECKERBOARD $19.50 |
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1.25ct FULL FIRE Natural Genuine Gemstone Oval Cut Red Orange Spessartite Garnet $16.99 |
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2.00Ct. Natural Gem Stone Gorgeous Set Oval Round Rich Orange Spessartite Garnet $9.99 |
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3.75cts INTENSE Red SPESSARTITE GARNET Natural Faceted GEMSTONE OVAL CUT $29.50 |
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1.36CT.FIRE FLASH! OVAL FACET ORANGE NATURAL SPESSARTITE GARNET NAMIBIA $0.99 |
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2.58CT.FIRE FLASH! OVAL FACET ORANGE & RED NATURAL SPESSARTITE GARNET NAMIBIA $0.99 |
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Garnet-spessartite-oval,3.08ct,(1)9.1×7.1×4.9mm,GS-A19,cut from natural crystal $55.84 |
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1.16ct- 7.1×5.2mm Oval Mandarin Orange Spessartite Garnet 100% Natural Namibia $0.99 |
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3.60 CT. GLEAMIMG ORANGE OVAL CAB SPESSARTITE GARNET NATURAL $0.59 |
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2.03ct Amazing Oval Orange Spessartite Garnet $35.00 |
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6.42ct. NATURAL ORANGE SPESSARTITE GARNET CABOCHON OVAL SHAPE $0.99 |
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10.15 CTS TOP OVAL MANDARIN ORANGE SPESSARTITE GARNET $579.00 |
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3.86 CT AAA! NATURAL! RED AFRICA SPESSARTITE GARNET OVAL $0.99 |
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3.50ct TOP FANTA ORANGE OVAL SPESSARTITE GARNET PAIR $249.00 |
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VVS Oval Orange Red Spessartite 2.10ct $0.99 |
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Big! 1.15 ct Top Lustre Rare Spessartite Garnet Mozambiq Fanta Orange Oval IF NR $9.99 |
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Big 9.20Ct Top Luster Excellent Fanta Orange Spessartite Cab Garnet Oval – NR! $9.99 |
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NATURAL OVAL RICH RED ORANGE NAMIBIA SPESSARTITE GARNET 1.91 CT.NR FREE COMBINE $0.99 |
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Huge! 1.35 Carat Top Excellent Rare Fanta Orange Spessartite Garnet Oval IF -@NR $9.99 |
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HUGE 1.50 Cts EXCELLENT TOP LUSTRE ORANGE SPESSARTITE GARNET MOZAMBIQUE OVAL $NR $9.99 |
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5.90ct SPLENDID NATURAL OVAL RED SPESSARTITE GARNET $319.20 |
