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Gemtype Color Shape Weight Size Date Clarity Price Origin
You Selected (40): Marquise Shape 18x9 mm Gems Clear All
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ID: 3521651 pcs
5.88ct Amethyst
18.04mm x 8.97mm x 6.69mm
USD 41.16
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ID: 3513621 pcs
4.49ct Amethyst
17.30mm x 8.99mm x 5.45mm
USD 31.43
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ID: 3584151 pcs
6.75ct Amethyst
18.26mm x 9.05mm x 7.51mm
USD 41.24
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ID: 3514071 pcs
5.35ct Amethyst
17.84mm x 8.96mm x 5.84mm
USD 37.45
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ID: 3526751 pcs
4.97ct Amethyst
17.91mm x 9.17mm x 5.76mm
USD 34.79
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ID: 3526711 pcs
5.15ct Amethyst
17.64mm x 9.02mm x 6.28mm
USD 36.05
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ID: 3513601 pcs
6.22ct Amethyst
18.10mm x 9.00mm x 6.99mm
USD 43.54
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ID: 3872151 pcs
4.54ct Jadeite
18.60mm x 9.08mm x 3.19mm
USD 22.70
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ID: 3585091 pcs
6.66ct Amethyst
18.17mm x 9.24mm x 6.82mm
USD 40.69
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ID: 3513871 pcs
5.95ct Amethyst
17.76mm x 9.35mm x 6.49mm
USD 41.65
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ID: 3865091 pcs
4.54ct Ruby in Fuchsite
18.72mm x 9.02mm x 2.65mm
USD 30.60
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ID: 3513891 pcs
5.79ct Amethyst
17.82mm x 8.83mm x 6.25mm
USD 40.53
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ID: 3524821 pcs
6.63ct Amethyst
18.35mm x 9.28mm x 7.53mm
USD 46.41
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ID: 3513951 pcs
5.85ct Amethyst
18.00mm x 9.17mm x 6.54mm
USD 40.95
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ID: 3865061 pcs
3.90ct Ruby in Fuchsite
17.86mm x 9.32mm x 2.46mm
USD 26.29
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ID: 3513991 pcs
7.04ct Amethyst
18.37mm x 9.32mm x 7.66mm
USD 49.28
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ID: 3523371 pcs
6.48ct Amethyst
17.95mm x 8.95mm x 7.84mm
USD 45.36
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ID: 3872171 pcs
4.90ct Jadeite
18.70mm x 8.79mm x 3.31mm
USD 24.50
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ID: 3524761 pcs
5.15ct Amethyst
17.59mm x 9.04mm x 6.13mm
USD 36.05
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ID: 3865834 pcs
11.26ctw Ruby in Fuchsite
17.63mm x 9.06mm x 2.36mm
USD 75.89
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ID: 3866961 pcs
4.77ct Ruby in Fuchsite
18.63mm x 8.88mm x 2.82mm
USD 32.15
Item in Stock
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Marquise Shape 18x9 mm Gems
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 18 mm x 9 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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Size and Weight

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart