Calibrated Marquise Cut Gemstones in Size 12x6 mm

Some people by gems by color or price, but for many, it is best to buy gems by shape and size - especially if you're in need of a gem to replace a previous item that was lost or damaged. Calibrated marquise shaped facet cut gems, gemstone carvings and cabochons available in 12 mm x 6 mm sizes. For the largest selection of colored gemstones, Shop GemSelect Online.

As a general guideline, when it comes to calibrated gems, they are not usually expected to be cut to exact measurements and specifications. But rather, they're cut with slight variance in size, though the close approximatation in size is not clearly defined, there are general guidelines for what is considered acceptable. Obviously larger and heavy carat weight stones allow more room in size for variance, while smaller stones may leave little to none. This means a large 30mm calibrated gemstone, could actually be closer to 31 millimeters. For this reason, we recommend to always view the exact size in addition to the calibrated size details. The exact size will inform you of the variance you can expect. Some setting styles are more flexible with variance, such as prong settings, while other styles of mountings may need almost an exact size to the fraction of millimeter.

For calibrated gemstones weighing under one carat, most jewelry settings will accommodate a gem which is within 0.2 mm of the calibrated size in order to fit a standard setting. For gemstones that weigh over one carat, a larger variance is acceptable, often round shape settings will allow 0.3 mm or slightly higher even. This small variance can usually be accommodated for most standard style settings. Round-cut gemstones should also have a greater variance in acceptable size when it comes to calibration; in fact it is usually possible to mount a round stone of any size in the closest standard setting.

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Gemstones A-Z

Buy Marquise Shape 12x6 mm Gems

0.86 ct Cushion Cut Color-Change Diaspore, 7.1 x 5.1 mm From Brazil

1.57 carat Oval Demantoid Garnet, loose Certified Demantoid Garnet from Namibia, Natural Untreated Gems, 4.8 x 3.9 mm

2.75 ct Oval Malachite, 8.9 x 6.9 mm From Congo

0.72 carat Emerald Cut Emerald, loose Certified Emerald from Colombia, Natural Gem, 4.8 x 4.8 mm

6.47 ct Baguette Rainbow Moonstone, 15.2 x 7.8 mm From the United States

4.52 ct Oval Rose Cut Smoky Quartz, 9.6 x 7.7 mm From Brazil

5.49 ct Loose Oval Cut Mystic Quartz, 13.1 x 11.1 mm From Brazil

22.38 carat Swiss Blue Topaz, Oval loose Topaz from Brazil, Natural Gem, 19.9 x 14.8 mm

7.18 ct Round Rutile Quartz, 12 mm From India

13.86 ct Yellow Apatite, 16.3 x 14.3 mm Oval Cut From Madagascar

2.25 ct Orange Sunstone, 8.3 x 6.2 mm Oval Cut From India

0.5 carat London Blue Topaz, Oval loose Topaz from Brazil, Natural Gem, 5.9 x 3.9 mm

1.72 ct Pink Morganite, 8.8 x 6.8 mm Oval Cut From Afghanistan

0.54 carat Orange Spessartite Garnet, Pear Shape loose Spessartite Garnet from Mozambique, Natural Untreated Gem, 5.1 x 4.1 mm

38.13 ct Pencil Cut Jasper, 35.5 mm From India

16.18 ct Oval Rose Quartz, 17.9 x 14.8 mm From South Africa

3.28 carat Yellow Citrine, Oval loose Citrine from Brazil, Natural Untreated Gem, 11.1 x 9.1 mm

3.62 carat Blue Tanzanite, Oval loose Tanzanite from Tanzania, Natural Gems, 8.1 x 6.2 mm

1.94 carat Sky Blue Topaz, loose Topaz from Brazil, Natural Gems, 7.1 x 5 mm

5.56 carat Cushion Amethyst, loose Certified Amethyst from Brazil, Natural Untreated Gem, 15.2 x 9.1 mm

9.04 ct Cushion Ruby-Zoisite, 15.5 x 9.9 mm From Tanzania

2.53 carat White Zircon, Oval loose Zircon from Cambodia, Natural Gems, 7.1 x 5.1 mm

62.08 ct Yellow Quartz, 26.2 x 21.9 mm Cushion Checkerboard From Brazil

1.53 ct Oval Cut Kornerupine, 8.3 x 5.8 mm From Sri Lanka

1.86 carat Orange Hessonite Garnet, Oval loose Hessonite Garnet from Madagascar, Natural Untreated Gem, 8.2 x 6.8 mm

12.76 ct Round Cut Smoky Quartz, 17.6 mm From Brazil

1.44 carat Green Tourmaline, Round Cabochon loose Tourmaline from Mozambique, Natural Untreated Gem, 6.1 mm

0.56 carat Blue Sapphire, Trillion-Cut loose Sapphire from Madagascar, Natural Gem, 5.3 x 5.1 mm

39.16 ct Oval Rutile Quartz, 34.4 x 23.4 mm From India

1.33 carat Emerald Cut Emerald, loose Certified Emerald from Colombia, Natural Gem, 6.6 x 6.3 mm

1.01 ct Blue Kyanite, 6 mm Round Cut From Nepal

1.88 carat Pink Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 7.9 x 6.2 mm

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