2.51 Carat H-SI1 Ideal Cut Princess Diamond

Diamond Assistant

Hover over a diamond characteristic to learn more

Choose a Diamond

You can choose a diamond first or start by choosing setting.

1. Choose a diamond
2. Choose a matching setting
3. Review your results in "My Design" before checkout

Choose a Setting

You can choose a setting first or start by choosing diamond.

1. Choose a setting
2. Choose a matching diamond
3. Review your results in "My Design" before checkout

My Design

Review your diamond and setting selections before proceeding to our convenient checkout.

Shape

Diamonds are available in a variety of shapes, which emphasize its specific features. The most popular diamond shapes are the Round, Princess, Emerald, Asscher, Oval, Radiant, Pear, Heart, Marquise, and Cushion Cut.

Color

A diamond’s color is an important element of its quality. In a white diamond, the less body color present, the greater the value of the diamond. The GIA grades diamonds on a scale of D (colorless) to Z (noticeable color).

Cut

The cut of a diamond influences how effectively it reflects light. Well-cut diamonds appear fiery and brilliant and allow light to enter the stone and be reflected around the facets before exiting the stone through the top. Poorly-cut diamonds can appear lifeless and dark, despite their clarity or color grade.

Carat Weight

The carat is the unit used to measure a diamond or gemstone’s weight. A single carat weighs 200 milligrams. In general, the larger the diamond, the higher its value - although cut, color, and clarity also play a significant role in value.

Clarity

Clarity refers to the presence of imperfections, flaws and blemishes inside or on the surface of a diamond. The GIA grades diamond clarity under 10X magnification on a scale that ranges from Flawless (FL) to I2-3 (Included)—diamonds with the least amount of flaws having the highest clarity grading. A diamond’s clarity has a significant impact on its value.

Polish

Polish refers to the smoothness of a diamond’s facets. Polish can affect a diamond’s brilliance. The GIA grades polish as follows: Excellent, Very Good, Good, Fair or Poor.

Symmetry

A diamond’s symmetry refers to how well the facets of diamond are aligned and arranged around the stone. The more symmetrical the diamond, the more fire and brilliance it will display. Symmetry is more important in diamonds that have very high clarity grades.

Laboratory

All of our diamonds are graded by the 3 most reputable diamond grading laboratories in the world: GIA, AGS & IGI.
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Price

Select a price range that fits your budget.

Depth

Depth refers to the height of the diamond, as measured from the top-table facet to bottom-culet facet. A diamond’s depth plays a key role in giving brilliance to the stone. If a diamond is cut too shallow or too deep, light will be lost, resulting in diminished brilliance.

Table

The table is the diamond’s largest facet, situated at the top. The table is the main entry and exit point for light. Table width is quoted as a percentage.

Fluorescence

A diamond’s fluorescence is its tendency to glow, usually blue, under ultraviolet light. Some studies indicate that a strong blue fluorescence is associated with a milky or hazy appearance in regular light, although the GIA has indicated that diamond fluorescence is usually imperceptible to the average consumer.

Girdle

The girdle is the outer edge of a diamond—the thin unpolished band around the widest part of a diamond. The girdle protects the edge of the stone from chipping.

Culet

The culet is the face on the bottom of a diamond that looks like a point. The culet is often polished to be flat during the manufacturing process.

Measurements

Since no two diamonds are identical in proportion, a diamond’s measurements are primarily used for identification purposes. A diamond’s measurements, such as its length-to-width ratio, determine its overall beauty and brilliance.

Certificate

A diamond certificate, or grading report, is a blueprint and evaluation of a loose diamond. A certificate will report the measurements, carat weight, clarity, cut, and other key characteristics of the diamond. A diamond certificate from a reputable agency assures the quality of the diamond.

Fluorescence

Emission of visible light by a material when it is exposed to ultra violet radiation. Learn more.

Find your ring size

Having trouble determining the correct size for your engagement ring or wedding band? Here are some tips. Learn more

Contact a Representative for more information

Our knowledgeable Customer Service Representatives are available by phone and chat to assist you with any questions or concerns you may have.

They are available 24 hours a day, 7 days a week.

Real Diamond Photos

James Allen uses unprecedented technology to photograph each diamond that we sell. By providing actual photos of our inventory, you can examine each diamond exactly as a jeweler can. We are the first site to offer this important feature, and the only site to offer such a large number of real photos. Plus, with our Virtual Loupe, you can see any of our diamonds at 30X magnification. We understand the significance of purchasing a diamond, and we guarantee you will find what you are looking for. At James Allen, what you see is what you get.

Metal

Select the type of metal you prefer. Learn More

Diamond Quality

Many factors contribute to the overall quality of a diamond, including cut, carat, color and clarity. Learn More

Pavilion Angle

The pavilion angle is the angle of the pavilion facets relative to the girdle plane. Pavilion angle is a very important component of a diamond’s proportions, because it greatly affects the amount of brilliance a diamond will display.

Crown Angle

The crown is the top part of the diamond, from the girdle to the table. The crown angle in a well-cut diamond should be 33 to 35 degrees.

Crown %

Crown % refers to the distance from the diameter of the diamond to the bottom-culet facet. The percentage is calculated as follows: Distance from diameter to bottom-culet facet/diameter.

Pavilion %

Pavilion % refers to the distance from the top-table facet to the diameter of the diamond. The percentage is calculated as follows: Distance from top-table facet to diameter/diameter.

L/W Ratio

The L/W Ratio of a diamond compares its Length to Width, resulting in a ratio that can be helpful when purchasing a fancy shape diamond. A ratio of 1.0 indicates a diamond that is perfectly square or round. As the ratio increases, the diamond becomes more elongated in shape.