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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The gem stone always has a great selection of beautiful stones. The calibrated stone fit my ring perfectly. Thank you gem select !

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Gemstones A-Z

Buy Marquise Shape 12x6 mm Gems

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

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

9.81 ct Flower Cut Smoky Quartz, 11.4 x 10.1 mm From Brazil

1.24 carat Green Tourmaline, Emerald Cut loose Tourmaline from Mozambique, Natural Untreated Gem, 15.5 x 3 mm

35.2 ct Oval Checkerboard Labradorite, 33.8 x 18.9 mm From Madagascar

0.54 ct Loose Violet Sapphire, 5.9 x 4.2 mm Oval Cut From Tanzania

24.02 ct Amethyst Geode Slice, 22.7 x 22.6 mm From Brazil

1.5 carat Blue Tanzanite, Pear Shape loose Tanzanite from Tanzania, Natural Gems, 5.1 x 3.2 mm

1.6 carat Oval Demantoid Garnet, loose Certified Demantoid Garnet from Namibia, Natural Untreated Gems, 4.9 x 4 mm

5.15 ct Pink Kunzite, 10.9 x 7.9 mm Octagon Cut From Afghanistan

1.93 carat Blue Topaz, Emerald-Cut loose Topaz from Brazil, Natural Gem, 8 x 6 mm

2.13 ct Oval Cut Black Opal, 12.6 x 9.4 mm From Ethiopia

0.62 ct Blue Green Apatite, 5.8 x 4.3 mm Oval Cut From Madagascar

6.03 ct Yellow Quartz, 12 x 11.8 mm Asscher Cut From Brazil

2.03 carat Orange Hessonite Garnet, Cushion loose Hessonite Garnet from Sri Lanka, Natural Untreated Gem, 6.9 x 6.8 mm

7.54 carat Pear Rutile Quartz, loose Certified Rutile Quartz from India, Natural Untreated Gem, 15 x 11 mm

0.74 carat Pear Shape Color-Change Diaspore, loose Certified Color-Change Diaspore from Turkey, Natural Untreated Gem, 8.9 x 4.2 mm

14.53 ct Yellow Quartz, 12.2 x 12.1 mm Carved From Brazil

1.6 ct Yellow Beryl, 9 x 7 mm Oval Cut From Madagascar

1.99 ct Cushion Cut Peridot, 8.3 x 6.2 mm From Myanmar

0.57 carat Oval Demantoid Garnet, loose Certified Demantoid Garnet from Namibia, Natural Untreated Gem, 6.2 x 4.2 mm

7.49 ct Green Agate, 10 x 8.9 mm Oval Cut From India

1.13 carat Orange Sunstone, Oval loose Sunstone from India, Natural Untreated Gem, 8 x 6.2 mm

1.37 carat Blue Topaz, Marquise-Cut loose Topaz from Brazil, Natural Gem, 9.7 x 5 mm

7.18 carat White Topaz, Cushion loose Topaz from Brazil, Natural Untreated Gem, 12.2 x 10.1 mm

1.21 carat Oval Ruby, loose Certified Ruby from Madagascar, Natural Gem, 6.9 x 5 mm

1.25 ct Yellow Beryl, 8.2 x 6.2 mm Oval Cut From Madagascar

1.11 carat Orange Hessonite Garnet, Emerald Cut loose Hessonite Garnet from Madagascar, Natural Untreated Gem, 6.9 x 5 mm

3.07 ct Diamond Cut Andalusite, 3.3 mm From Brazil

32.97 ct Fancy Moss Agate, 30.4 x 15.1 mm From India

4.77 carat Yellow Citrine, Oval loose Citrine from Brazil, Natural Untreated Gem, 12.4 x 10 mm

3.34 carat Blue Green Fluorite, Oval loose Fluorite from India, Natural Untreated Gem, 9.5 x 7.6 mm

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