Rings・ Necklaces・ Earrings・ Bracelets・ Diamonds

Natural Loose Diamonds

天然ダイヤモンドルース

Discover a world of natural diamonds in our extensive loose diamond collection.

From classic round cuts to unique fancy shapes and vibrant colors, we have the perfect diamond to suit your style.

Our easy-to-use diamond filter allows you to find your dream diamond based on your budget and preferences.

shape

形状

Round

Heart

Princess

Emerald

Oval

Cushion

Pear

Radiant

Marquise

Trilliant

Others

Rare Shapes

color

色

clarity

クラリティ

VVS2

VVS1

VS2

VS1

SI2

SI1

carat

カラット

0.50-0.99

1.00-1.99

2.00-2.99

price

価格

~100k Yen

100k~200k Yen

200k~350k Yen

350k~600k Yen

600k～1m Yen

1m~1.5m Yen

1.5m Yen~

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Showing 116 of 116

Natural Loose Natural Diamond 0.542ct Very Light Purplish Pink Oval

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Natural Loose Natural Diamond 0.62ct Colorless E Cushion

Regular price ¥260,000 (Tax incl.)

Unit price per
Natural Loose Natural Diamond 1.006ct Near Colorless G Cushion

Regular price ¥780,000 (Tax incl.)

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Natural Loose Natural Diamond 1ct Near Colorless H Cushion

Regular price ¥570,000 (Tax incl.)

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Natural Loose Natural Diamond 2.038ct Light Yellow S Cushion

Regular price ¥1,150,000 (Tax incl.)

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Natural Loose Natural Diamond 1.514ct Fancy Deep Brownish Greenish Yellow Cushion

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Natural Loose Natural Diamond 0.502ct Very Light Orangy Pink Cushion

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Natural Loose Natural Diamond 0.8ct Faint Pink Cushion

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Natural Loose Natural Diamond 2.075ct Near Colorless G Baguette

Regular price ¥1,390,000 (Tax incl.)

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Natural Loose Natural Diamond 0.7ct Colorless E Princess-cut

Regular price ¥370,000 (Tax incl.)

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Natural Loose Natural Diamond 1.029ct Colorless E Princess

Regular price ¥960,000 (Tax incl.)

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Natural Loose Natural Diamond 1.011ct Near Colorless H Princess-cut

Regular price ¥572,000 (Tax incl.)

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Natural Loose Natural Diamond 0.7ct Colorless E Pear

Regular price ¥390,000 (Tax incl.)

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Natural Loose Natural Diamond 0.569ct Light Pink Pear

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Natural Loose Natural Diamond 0.7ct Light Pink Pear

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Natural Loose Natural Diamond 0.836ct Very Light Pink Pear

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Natural Loose Natural Diamond Light Purplish Pink 0.722ct Pear

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Natural Loose Natural Diamond 1.061ct Very Light Brown Pear

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Natural Loose Natural Diamond 1.029ct Faint Green Pear

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Natural Loose Natural Diamond 0.513ct Very Light Pink Marquise

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Natural Loose Natural Diamond 1.102ct Light Yellow S Round

Regular price ¥480,000 (Tax incl.)

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Natural Loose Natural Diamond 0.523ct Very Light Purplish Pink Round

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Natural Loose Natural Diamond 0.838ct Colorless F Radiant

Regular price ¥410,000 (Tax incl.)

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Natural Loose Natural Diamond 1ct Colorless F Radiant

Regular price ¥838,000 (Tax incl.)

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Natural Loose Natural Diamond 0.95ct Near Colorless G Radiant

Regular price ¥580,000 (Tax incl.)

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Natural Loose Natural Diamond 0.62ct Near Colorless H Radiant

Regular price ¥227,000 (Tax incl.)

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Natural Loose Natural Diamond 0.516ct Light Orangy Pink Radiant

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Natural Loose Natural Diamond 0.715ct Very Light Pink Radiant

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Natural Loose Natural Diamond 1.01ct Fancy Yellow Cushion

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Natural Loose Natural Diamond 0.93ct Very Light Pink Radiant

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Natural Loose Natural Diamond 1.129ct Very Light Pink Radiant

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Natural Loose Natural Diamond 1.367ct Very Light Pink Radiant

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Natural Loose Natural Diamond 0.574ct Faint Pink Octagon

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Natural Loose Natural Diamond 1.03ct Colorless D Square-Emerald

Regular price ¥880,000 (Tax incl.)

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Natural Loose Natural Diamond 0.905ct Colorless E Heart

Regular price ¥550,000 (Tax incl.)

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Natural Loose Natural Diamond 1.533ct Near Colorless G Princess-cut

Regular price ¥1,150,000 (Tax incl.)

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Natural Loose Natural Diamond 5.01ct M Faint Yellow VS1 Oval-cut

Regular price ¥5,500,000 (Tax incl.)

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Natural Loose Natural Diamond 3.0ct Colorless D Princess-cut

Regular price ¥6,650,000 (Tax incl.)

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Natural Loose Natural Diamond 1.52ct Colorless F Cushion-cut

Regular price ¥1,250,000 (Tax incl.)

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Natural Loose Natural Diamond 1.787ct Colorless E Princess-cut

Regular price ¥1,780,000 (Tax incl.)

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Natural Loose Natural Diamond 0.702ct Colorless F Trilliant-cut

Regular price ¥374,000 (Tax incl.)

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Natural Loose Natural Diamond 10.016ct Very Light Yellow N Oval

Regular price ¥13,500,000 (Tax incl.)

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Natural Loose Natural Diamond 0.906ct Colorless D Oval

Regular price ¥660,000 (Tax incl.)

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Natural Loose Natural Diamond 0.558ct Fancy Deep Brownish Yellow Oval

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Natural Loose Natural Diamond 2.568ct Fancy Intense Orangy Yellow Oval

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Natural Loose Natural Diamond 3.011ct Very Light Yellow N Oval

Regular price ¥2,400,000 (Tax incl.)

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Natural Loose Natural Diamond 1.04ct Very Light Yellow N Oval

Regular price ¥400,000 (Tax incl.)

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Natural Loose Natural Diamond 1.09ct Light Green Oval

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Natural Loose Natural Diamond 0.81ct Near Colorless H Cushion

Regular price ¥340,000 (Tax incl.)

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Natural Loose Natural Diamond 2.091ct Faint Yellow K Trilliant

Regular price ¥740,000 (Tax incl.)

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Natural Loose Natural Diamond 3.097ct Near Colorless I Princess-cut

Regular price ¥4,268,000 (Tax incl.)

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Natural Loose Natural Diamond 0.638ct Fancy Light Yellow Princess-cut

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Natural Loose Natural Diamond 0.703ct Colorless D Pear

Regular price ¥407,000 (Tax incl.)

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Natural Loose Natural Diamond 0.504ct Fancy Deep Yellow Pear

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Natural Loose Natural Diamond 1.549ct Fancy Yellow Pear

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Natural Loose Natural Diamond 0.707ct Colorless E Marquise

Regular price ¥330,000 (Tax incl.)

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Natural Loose Natural Diamond 0.927ct Near Colorless G Marquise

Regular price ¥420,000 (Tax incl.)

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Natural Loose Natural Diamond 2.02ct Near Colorless G Marquise

Regular price ¥3,200,000 (Tax incl.)

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Natural Loose Natural Diamond 1.05ct Near Colorless G Round

Regular price ¥740,000 (Tax incl.)

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Natural Loose Natural Diamond 1.024ct Near Colorless I Round

Regular price ¥620,000 (Tax incl.)

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Natural Loose Natural Diamond 3.195ct Faint Yellow M Radiant Cut

Regular price ¥2,090,000 (Tax incl.)

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Natural Loose Natural Diamond 0.79ct Fancy Yellow Radiant

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Natural Loose Natural Diamond 0.915ct Fancy Yellow Radiant

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Natural Loose Natural Diamond 0.826ct Light Purplish Pink Radiant

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Natural Loose Natural Diamond 2ct Faint Yellow M Rose-cut

Regular price ¥760,000 (Tax incl.)

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Natural Loose Natural Diamond 1.004ct Colorless D Emerald-cut

Regular price ¥780,000 (Tax incl.)

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Natural Loose Natural Diamond 2.017ct Colorless D Emerald-cut

Regular price ¥4,420,000 (Tax incl.)

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Natural Loose Natural Diamond 1.73ct Colorless D Emerald-cut

Regular price ¥2,960,000 (Tax incl.)

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Natural Loose Natural Diamond 1.68ct Colorless D Cushion

Regular price ¥2,834,000 (Tax incl.)

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Natural Loose Natural Diamond 3.01ct Colorless E Cushion

Regular price ¥9,175,000 (Tax incl.)

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Natural Loose Natural Diamond 1.009ct Very Light Yellow N Cushion

Regular price ¥250,000 (Tax incl.)

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Natural Loose Natural Diamond 1.05ct Light Yellow W Cushion

Regular price ¥420,000 (Tax incl.)

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Natural Loose Natural Diamond 1.53ct Very Light Greenish Yellow Cushion

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Natural Loose Natural Diamond 1.005ct Fancy Intense Yellow Cushion

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Natural Loose Natural Diamond 1.0ct Fancy Intense Yellow Cushion

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Natural Loose Natural Diamond 1.51ct Fancy Vivid Yellow Cushion

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Natural Loose Natural Diamond 0.527ct Fancy Vivid Orangy Yellow Cushion

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Natural Loose Natural Diamond 0.529ct Fancy Vivid Orangy Yellow Cushion

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Natural Loose Natural Diamond 0.615ct Fancy Vivid Orangy Yellow Cushion

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Natural Loose Natural Diamond 0.787ct Pink Cushion

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Natural Loose Natural Diamond 1.03ct Fancy Intense Green Cushion

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Natural Loose Natural Diamond 2.013ct Light Greenish Yellow Cushion

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Natural Loose Natural Diamond 0.772ct Light Yellow S Cushion

Regular price ¥140,000 (Tax incl.)

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Natural Loose Natural Diamond 1.07ct Near Colorless G

Regular price ¥760,000 (Tax incl.)

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Natural Loose Natural Diamond 1.02ct Near Colorless G Trilliant-cut

Regular price ¥448,000 (Tax incl.)

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Natural Loose Natural Diamond 4.163ct Fancy Light Yellowish Brown Trilliant

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Natural Loose Natural Diamond 0.513ct Colorless D Baguette

Regular price ¥176,000 (Tax incl.)

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Natural Loose Natural Diamond 0.912ct Faint Yellow K Princess-cut

Regular price ¥250,000 (Tax incl.)

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Natural Loose Natural Diamond 1.07ct Fancy Yellow Princess-cut

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Natural Loose Natural Diamond 2.26ct Colorless F Pear

Regular price ¥5,810,000 (Tax incl.)

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Natural Loose Natural Diamond 1.018ct Near Colorless H Pear

Regular price ¥710,000 (Tax incl.)

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Natural Loose Natural Diamond 1.028ct Fancy Greenish Yellow Pear

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Natural Loose Natural Diamond 0.697ct Fancy Dark Brownish Yellow

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Natural Loose Natural Diamond 0.808ct Light Bluish Green Pear

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Natural Loose Natural Diamond 1.002ct Colorless D Marquise

Regular price ¥710,000 (Tax incl.)

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Natural Loose Natural Diamond 1ct Faint Yellow M Marquise

Regular price ¥390,000 (Tax incl.)

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Natural Loose Natural Diamond 3.015ct Light Yellow S Marquise

Regular price ¥2,398,000 (Tax incl.)

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Natural Loose Natural Diamond 0.561ct Very Light Purplish Pink Marquise

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Natural Loose Natural Diamond 1.053ct Near Colorless H Round

Regular price ¥540,000 (Tax incl.)

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Natural Loose Natural Diamond 1.069ct Colorless F Round

Regular price ¥980,000 (Tax incl.)

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Natural Loose Natural Diamond 1.585ct Near Colorless H Radiant

Regular price ¥1,820,000 (Tax incl.)

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Natural Loose Natural Diamond 1.561ct Light Yellow S Emerald-cut

Regular price ¥490,000 (Tax incl.)

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Natural Loose Natural Diamond 1.03ct Near Colorless G Rectangular

Regular price ¥630,000 (Tax incl.)

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Natural Loose Natural Diamond 0.52ct Fancy Orangy Pink Radiant

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Natural Loose Natural Diamond 0.792ct Very Light Yellowish Green Cushion

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Natural Loose Natural Diamond 1.097ct Fancy Light Green Radiant

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Natural Loose Natural Diamond 1.52ct Fancy Yellow Radiant

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Natural Loose Natural Diamond 1.2ct Fancy Yellow Radiant

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Natural Loose Natural Diamond 0.839ct Fancy Yellow Radiant

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Natural Loose Natural Diamond 1.81ct Fancy Light Greenish Yellow Radiant

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Natural Loose Natural Diamond 1.036ct Near Colorless H

Regular price ¥598,000 (Tax incl.)

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Natural Loose Natural Diamond 1.07ct Colorless F VS1

Regular price ¥975,000 (Tax incl.)

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Natural Loose Natural Diamond 1.5ct Fancy Deep Yellow Heart

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Natural Loose Natural Diamond 0.74ct Colorless E Heart

Regular price ¥407,000 (Tax incl.)

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Natural Loose Natural Diamond 1.613ct Colorless E Emerald-cut

Regular price ¥1,570,000 (Tax incl.)

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Natural Loose Natural Diamond 0.998ct Colorless D Marquise

Regular price ¥450,000 (Tax incl.)

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How to Choose a Loose Diamond

What Is a Loose Diamond?

A loose diamond is a diamond in its unmounted state, before it has been set into a ring, necklace, or other piece of jewelry. Rather than choosing a finished piece, buying loose allows you to evaluate the stone itself — its quality, shape, and color — on its own merits before deciding on a setting. At Weiss, our loose diamond collection spans colorless stones as well as fancy color diamonds in pink, yellow, green, and blue, available in a wide range of shapes including round, cushion, emerald, radiant, and pear. Every loose diamond comes with certification from GIA, CGL, HRD, or IGI, providing objective proof of quality.

Choosing by the 4Cs

A diamond's value is assessed against four criteria known as the 4Cs: Carat (weight), Cut (the proportions that determine brilliance), Color (how close to colorless a stone is), and Clarity (the absence of inclusions). It isn't necessary to maximize every category — a VS to SI clarity grade is often eye-clean, for example, which lets you prioritize carat weight within the same budget instead. Fancy color diamonds work in reverse on the color axis: the more saturated and vivid the color, the higher the value, unlike colorless diamonds where less color is preferred. We're happy to talk through which of the 4Cs matters most for your budget and the look you're going for.

Setting Your Diamond

Once you've selected a loose diamond, we can set it into a ring, necklace, or earrings in your choice of design and metal — 18K yellow, white, or rose gold, or platinum. This approach is especially popular for engagement rings, where buyers want to be involved in choosing the stone itself rather than selecting from a pre-made piece. Our loose diamonds start from ¥227,000, with rare fancy color and larger carat stones available at higher price points. To discuss a custom setting, contact us.

Frequently Asked Questions

What is a loose diamond?

A loose diamond is a diamond in its unmounted state, before it has been set into a ring, necklace, or other piece of jewelry. Buying loose allows you to evaluate the stone's quality, shape, and color on its own before choosing how it's set.

What are the benefits of buying a loose diamond?

Buying loose lets you carefully compare stone quality (carat, cut, color, and clarity) and gives you full freedom over the final design, rather than choosing from pre-made pieces. This is especially popular for engagement rings, where buyers want to be involved in selecting the stone itself.

What are the 4Cs?

The 4Cs are the four criteria used to assess a diamond's value: Carat (weight), Cut (the proportions that determine brilliance), Color (how close to colorless a stone is), and Clarity (the absence of inclusions). Fancy color diamonds are evaluated in reverse on color — more saturated, vivid color is valued higher, unlike colorless diamonds.

Do you carry fancy color diamonds?

Yes. We carry a wide selection of loose fancy color diamonds including pink, yellow, green, blue, brown, and purple. All are certified as natural color by an independent gemological laboratory.

Are your loose diamonds certified?

Yes. All loose diamonds at Weiss come with certification from GIA, CGL, HRD, or IGI, documenting carat weight, cut, color, and clarity, and confirming the stone is natural.

Can I have my loose diamond set into a ring or necklace?

Yes. We offer custom settings in your choice of design and metal, including 18K yellow, white, and rose gold, and platinum. This is a popular option for engagement rings and other personal pieces. Contact us to discuss your design.

Can I view loose diamonds in person before purchasing?

Yes. Our appointment-only office is in Okachimachi, Tokyo. Fancy color diamonds in particular can look different under different lighting, so an in-person viewing is recommended. Please book an appointment through our contact page or by phone.