Sapphire Weight and Size Chart

Visually, sapphires and diamonds of the same carat weight may vary in sizes. This is because the density of sapphires are different from the density of diamonds or other gemstones. Sapphires tend to be heavier than diamonds. Therefore a 1 carat sapphire may look smaller than a 1 carat diamond.

Some sapphires are calibrated and standardized for ease of use. Some sapphires are custom cut for a specific setting and does not fit these standardizations, and these may be far more valuable than the calibrated sapphires.

Unlike diamonds, sapphires are all about color. A skilled lapidarist cuts a rough sapphire in order to enhance its color. He takes into account the size of the rough sapphire and its inclusions when deciding the shape and size of the final masterpiece.

A standard size chart is a handy tool for a first time buyer. However, sapphire gemstone sizes may vary depending on the depth of the sapphire. Therefore please consider the following chart as just a rough point of reference.

Approximate Gemstone Weights - Round cut - size in millimeters
Gemstones	2mm	3mm	4mm	5mm	6mm	7mm	8mm	10mm
Alexandrite	.04	.12	.35	.63	1.30	2.15	2.90	5.20
Amethyst	.04	.10	.20	.40	.70	1.30	1.80	3.30
Aquamarine	.04	.10	.25	.45	.75	1.60	2.40	3.50
Blue Zircon	.06	.17	.36	.69	1.25	1.75	2.60	5.00
Citrine	.04	.10	.20	.40	.70	1.30	1.80	3.30
Diamond	.04	.10	.23	.47	.90	1.35	1.90	4.25
Emerald	.04	.10	.25	.45	.75	1.60	2.40	3.50
Garnet	.05	.13	.30	.60	1.00	1.60	2.50	5.75
Opal	.02	.09	.16	.34	.57	.83	1.30	2.00
Peridot	.05	.12	.26	.50	.85	1.25	2.00	5.25
Ruby	.05	.15	.34	.65	1.05	1.60	2.25	4.50
Sapphire	.05	.15	.34	.65	1.05	1.60	2.25	4.50
Topaz	.04	.11	.30	.56	1.00	1.95	2.50	5.75
Tourmaline	.04	.12	.24	.45	.75	1.55	2.00	3.00

Approximate Gemstone Weights - Oval cut - Size in millimeters
Gemstones	5x3	6x4	7x5	8x6	9x7	10x8	11x9	12x10	14x10	16x12	18x13	20x15
Alexandrite	.30	.61	.80	1.45	2.00	3.60	4.25	6.00	8.90	12.50	18.00	24.00
Amethyst	.23	.45	.85	1.25	1.75	2.40	3.20	4.50	6.50	11.00	14.00	16.00
Aquamarine	.20	.40	.75	1.10	1.75	2.25	3.00	4.25	6.20	9.20	10.60	14.50
Blue Zircon	.40	.75	1.45	2.00	2.85	4.00	5.60	7.50	8.20	13.50	17.50	23.00
Citrine	.23	.45	.85	1.25	1.75	2.40	3.20	4.50	6.50	11.00	14.00	16.00
Diamond	.25	.50	.75	1.40	2.00	3.00	4.00	5.00	8.00	11.50	16.00	21.50
Emerald	.20	.40	.75	1.10	1.75	2.25	3.00	4.25	6.20	9.20	10.60	14.50
Garnet	.25	.55	1.00	1.40	2.10	2.80	3.75	5.00	7.00	10.00	13.25	20.00
Opal	.16	.28	.47	.78	1.10	1.65	2.15	3.00	4.00	5.25	6.00	7.25
Peridot	.28	.50	.95	1.35	2.00	2.50	3.50	4.00	6.00	9.50	13.00	20.00
Ruby	.35	.60	1.00	1.55	2.20	3.15	3.80	6.00	7.25	12.00	14.00	20.00
Sapphire	.35	.60	1.00	1.55	2.20	3.15	3.80	6.00	7.25	12.00	14.00	20.00
Topaz	.27	.57	1.10	1.60	2.50	3.50	4.50	6.00	8.80	12.00	17.00	22.00
Tourmaline	.25	.50	.90	1.18	2.30	2.90	3.50	5.25	6.80	8.50	12.00	18.00

Approximate Gemstone Weights - Emerald Cut- size in millimeters
Gemstones	5x3	6x4	7x5	8x6	9x7	10x8	11x9	12x10	14x10	16x12	18x13	20x15
Alexandrite	.40	.70	1.30	2.60	3.60	4.20	6.00	8.50	9.90	14.50	22.00	27.00
Amethyst	.35	.55	1.00	1.60	2.25	2.90	4.20	5.60	7.25	13.00	17.00	22.00
Aquamarine	.25	.50	.80	1.40	2.00	3.00	4.30	4.75	7.75	13.50	17.00	22.00
Blue Zircon	.60	.85	1.70	2.35	3.90	4.50	6.20	7.01	8.95	14.30	19.90	28.70
Citrine	.35	.55	1.00	1.60	2.25	2.90	4.20	5.60	7.25	13.00	17.00	22.00
Diamond	.25	.50	1.00	1.50	3.00	4.00	5.00	7.80	8.80	13.00	20.00	25.50
Emerald	.25	.50	.80	1.40	2.00	3.00	4.30	4.75	7.75	13.50	17.00	22.00
Garnet	.40	.80	1.20	1.70	2.50	3.50	4.30	6.35	9.00	17.50	21.00	27.00
Opal	-	-	-	-	-	-	-	-	-	-	-	-
Peridot	.35	.60	1.00	1.70	2.25	3.80	5.25	6.25	8.80	17.00	20.00	26.00
Ruby	.55	.75	1.15	1.60	2.30	2.75	4.00	6.25	9.00	12.50	18.70	27.00
Sapphire	.55	.75	1.15	1.60	2.30	2.75	4.00	6.25	9.00	12.50	18.70	27.00
Topaz	.40	.65	1.25	2.40	3.40	4.00	5.75	8.00	9.50	14.00	21.00	26.00
Tourmaline	.30	.60	1.60	2.15	2.80	3.60	4.30	5.20	8.50	13.00	16.50	24.90

Approximate Gemstone Weights - Pear size in millimeters
Gemstones	5x3	6x4	7x5	8x6	9x6	10x7	13x8	14x10
Alexandrite	.30	.50	.85	1.10	2.10	3.60	6.60	8.80
Amethyst	.20	.35	.65	.85	1.25	1.70	4.00	5.00
Aquamarine	.20	.35	.65	.90	1.30	1.85	4.20	5.60
Blue Zircon	.30	.70	1.00	1.30	2.60	4.00	5.25	7.50
Citrine	.20	.35	.65	.85	1.30	1.70	4.00	5.00
Diamond	.25	.50	.75	1.00	1.50	2.00	3.50	5.00
Emerald	.20	.35	.65	.90	1.30	1.85	4.20	5.60
Garnet	.25	.40	1.00	1.15	1.30	1.80	3.50	5.80
Opal	.13	.22	.35	.50	.70	1.03	1.40	2.45
Peridot	.25	.45	.70	.80	1.10	1.40	3.40	4.75
Ruby	.30	.50	.75	1.00	1.85	2.50	4.75	7.90
Sapphire	.30	.50	.75	1.00	1.85	2.50	4.75	7.90
Topaz	.25	.50	1.00	1.10	2.00	3.50	6.50	8.50
Tourmaline	.35	.45	.60	.90	1.10	1.40	2.80	6.75

Approximate Gemstone Weights - Marquise/Navette - size in millimeters
Gemstones	4x2	6x3	8x4	10x5	12x6	14x7
Alexandrite	.07	.30	.70	1.25	2.10	3.50
Amethyst	.10	.20	.48	.90	1.59	2.45
Aquamarine	.08	.20	.50	.80	1.50	2.75
Blue Zircon	.13	.33	.75	1.25	1.95	3.00
Citrine	.10	.20	.48	.90	1.59	2.45
Diamond	.12	.25	.50	1.00	2.00	3.00
Emerald	.08	.20	.50	.80	1.50	2.75
Garnet	.09	.25	.60	1.20	2.00	2.85
Opal	.09	.17	.37	.59	1.00	1.25
Peridot	.10	.25	.50	1.00	2.00	2.55
Ruby	.13	.35	.75	1.15	2.20	3.00
Sapphire	.13	.35	.75	1.15	2.20	3.00
Topaz	.07	.30	.70	1.20	2.00	3.40
Tourmaline	.10	.30	.60	.85	1.55	2.20

Sapphire Conversion Rates

1 Gram = 5 Carats

1 Pearl Grain = .25 Carats

1 Pound = 453.584 Grams

1 Kilogram = 2.2046 Pounds

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