Cassiopeia Opal and Diamond Ring in 18K Yellow Gold

The ring size of an eternity ring determines its total carat weight. The total carat weight range reflects the difference in total carat weight between sizes. Learn more about carat weight information.

The listed carat weight for halo styles is based on a 6.5mm round center gemstone and may vary based on the size and shape of center gem. Learn more about carat weight information.

The ring size of an eternity ring determines its total number of gemstones. The total number of gemstones range reflects the difference in total number of gemstones between sizes.

All of our prices are in US$.

All of our prices are in US$.

Diamond cut should not be confused with shape. Shape refers to the general outward appearance of the diamond, not its reflective qualities. Brilliant Earth currently carries the following shapes:

Diamond cut should not be confused with shape. Shape refers to the general outward appearance of the diamond, not its reflective qualities. Brilliant Earth currently carries the following shapes:

Cut should not be confused with shape. Shape refers to the general outward appearance of the gemstone, not its reflective qualities. Brilliant Earth currently carries the following shapes:

Describes the alignment of the facets of the diamond. If facets are misaligned, the diamond may poorly reflect light. Symmetry is graded from Ideal / Excellent, Very Good, Good, Fair, or Poor. Symmetry grades of Good or higher have the least effect on the brilliance of the diamond and are suitable for the finest quality jewelry. Certain gem labs, such as Gemscan, incorporate Symmetry into an overall Cut grade.

Describes the alignment of the facets of the diamond. If facets are misaligned, the diamond may poorly reflect light. Symmetry is graded from Ideal / Excellent, Very Good, Good, Fair, or Poor. Symmetry grades of Good or higher have the least effect on the brilliance of the diamond and are suitable for the finest quality jewelry. Certain gem labs, such as Gemscan, incorporate Symmetry into an overall Cut grade.

The height of a gemstone, from the culet to the table. Depth % is the height of the diamond as a percentage of the girdle diameter.

The height of a gemstone, from the culet to the table. Depth % is the height of the diamond as a percentage of the girdle diameter.

Diamonds are given three measurements to specify their dimensions. For fancy shaped diamonds, the measurement specifies length x width x depth. The length is the larger dimension as you view the diamond from the top and the width is the smaller. The depth is the height of a gemstone, from the culet to the table. The measurements determine the length to width ratio and can indicate the quality of cut of the diamond.

For round diamonds, the measurement specifies diameter 1 x diameter 2 x depth. Round diamonds are never quite perfectly round given they are cut by humans. They are given two measurements for diameter to indicate the maximum and minimum diameter. These two diameters vary slightly, but should not vary by very much.

Describes the finish of the facets of the diamond. Polish is graded from Ideal, Excellent, Very Good, Good, Fair, or Poor. Polish grades of Good or higher have the least effect on the brilliance of the diamond and are suitable for the finest quality jewelry. Certain gem labs, such as Gemscan, incorporate Polish into an overall cut grade.

Vermeil (pronounced vehr-may) is sterling silver that is plated in a thick layer of gold, making it more resistant to signs of wear. Our vermeil is 14K yellow or rose gold that is a minimum of 2.5 microns thick.

Tantalum is a natural chemical earth metal. It belongs to a class of metals known as refractory metals, which are defined by their strong resistance to heat and wear.

Describes the finish of the facets of the diamond. Polish is graded from Ideal, Excellent, Very Good, Good, Fair, or Poor. Polish grades of Good or higher have the least effect on the brilliance of the diamond and are suitable for the finest quality jewelry. Certain gem labs, such as Gemscan, incorporate Polish into an overall cut grade.

The largest facet of a gemstone, located at the top. Table % is the table width as a percentage of the girdle diameter.

The largest facet of a gemstone, located at the top. Table % is the table width as a percentage of the girdle diameter.

The narrow rim around the widest part of a diamond, separating the crown from the pavillion.

The tiny facet at the bottom tip of a gemstone. The optimal culet should be pointed or very small (graded "small" or "none").

Describes the diamond's response to ultraviolet light. In diamonds with strong or very strong fluorescence, there may be some interference with the flow of light which causes a milky or oily appearance.

Describes the diamond's response to ultraviolet light. In diamonds with strong or very strong fluorescence, there may be some interference with the flow of light which causes a milky or oily appearance.

A diamond certificate or grading report provides an expert opinion on the quality of the diamond and is provided by an independent gemology lab. Trained gemologists with specialized equipment measure the weight and dimensions of the diamond and assess quality characteristics such as cut, color, and clarity. Brilliant Earth diamonds are certified by the world’s leading gem grading labs including GIA, IGI, HRD, and GCAL. If the diamond lab certificate is not available online, please contact us to request an electronic copy.

A diamond certificate or grading report provides an expert opinion on the quality of the diamond and is provided by an independent gemology lab. Trained gemologists with specialized equipment measure the weight and dimensions of the diamond and assess quality characteristics such as cut color, and clarity. Brilliant Earth diamonds are certified by the world’s leading gem grading labs including GIA, IGI, HRD, and GCAL and the agency who issues the Sustainably Rated Diamond Certification. If the certificate is not available online, please contact us to request an electronic copy.

We go above and beyond the current industry standards to offer Beyond Conflict Free Diamonds™ with a listed country of origin of Canada or Botswana Sort. Our select group of diamond suppliers demonstrate a robust chain of custody protocol for their diamonds and have the ability to track and segregate diamonds by country of origin.

These suppliers are required to source diamonds that originate from specific mine operations or specific countries that have demonstrated their commitment to follow internationally recognized labor, trade, and environmental standards. We also offer recycled diamonds, which are a naturally eco-friendly choice.

We go above and beyond the current industry standards to offer Beyond Conflict Free Diamonds™ with a listed country of origin of Canada or Botswana Sort. Our select group of diamond suppliers demonstrate a robust chain of custody protocol for their diamonds and have the ability to track and segregate diamonds by country of origin.

These suppliers are required to source diamonds that originate from specific mine operations or specific countries that have demonstrated their commitment to follow internationally recognized labor, trade, and environmental standards. We also offer recycled diamonds, which are a naturally eco-friendly choice.

Browse our diamonds according to general preferences and staff recommendations.

Our current diamond collections include:

• Glacier Collection: Our premium and rarest diamonds, exhibiting the most sparkle and brilliance
• Yosemite Collection: Beautiful diamonds offering an optimal balance between size and quality.
• Recommended Collection: Hand-selected by our staff gemologists to offer diamonds of unique beauty that maximize value for any budget. Diamonds are in stock and available immediately.

Length-to-Width Ratio –The length-to-width ratio compares the length of a diamond to its width to show how elongated a fancy-shaped diamond appears when viewed from the top. Length-to-width ratio is a matter of personal preference with some individuals preferring a more elongated shape and others a more equal or square shape. The most popular length-to-width ratios for fancy shapes are below.

Ex. A princess-cut diamond that measures 5.05 mm long by 5.00mm has a length-to-width ratio of 1.01 (5.05/5.00), and will appear perfectly square.

Most popular length-to-width ratios:
Princess: 1.00-1.05
Radiant: 1.00-1.05
Asscher: 1.00-1.05
Cushion: 1.00-1.05
Elongated Cushion: 1.20-1.49
Heart: 0.90-1.10
Emerald: 1.30-1.40
Oval: 1.30-1.70
Pear: 1.45-1.75
Marquise: 1.75-2.30

You may use a bank wire to pay for Brilliant Earth purchases of $500 or more. For US, Canadian, and Australian bank wires only, Brilliant Earth provides a 1.5% discount to your order. For Canadian, Australian, and other international bank wires, a $35 processing fee will apply to your order. Some financial institutions may also charge a fee for using a bank wire.

After you submit your order, Brilliant Earth will give you the account information you will need to provide to your bank to transfer funds from your account directly to a Brilliant Earth account. It may take a few days for your bank to process the bank wire. Once your bank has transferred the funds, Brilliant Earth is immediately notified and your purchase is processed. If you have any questions about the process involved in a bank wire, contact your bank or call Brilliant Earth at 614.756.0011.

Please note an ACH transfer is not the same as a wire transfer. At this time, Brilliant Earth does not accept ACH transfers.

The length of the chain will determine where the necklace will fall, whether choker length, at or below the collarbone, or at the neckline. We measure the length from the beginning of one end, to the end of the other, including the clasp (which may add an additional .75 inches). Different lengths are worn for different occasions and different outfits. The most common length is the 18" length, which typically falls at the collarbone. 16": Choker length. Accentuates her neckline. 18": At collarbone. Classic length. 20": A few inches below collarbone. 22": At or above neckline. For more dramatic, stylish look.

The dimensions of the gemstone are the length and width of a gemstone as it appears from the top view. Dimensions represent the size of the gemstone more accurately than carat weight.

For colored gemstones, dimensions are the best way of accurately measuring size. These dimensions are accurate plus or minus 0.2mm.

Color is used to describe the color present within a gemstone. Color is described in terms of tone and hue. Brilliant Earth carefully selects gemstones with even color distributed throughout the gemstone.

Clarity is used to describe the presence of impurities on and within the gemstone. If the clarity of gemstones is specified as "eye clean", no visible impurities or flaws will be seen with the unaided eye. If the gemstone is "moderately included," there may be moderate flaws that are visible upon examination.

Many aquamarines are heated in a controlled environment to ensure their blue color is as vibrant and pure as possible. This heat treatment is an accepted industry standard which mimics natural processes to maximize the beauty of the stone.

The length of the chain will determine where the necklace will fall, whether choker length, at or below the collarbone, or at the neckline. We measure the length from the beginning of one end, to the end of the other, including the clasp (which may add an additional .75 inches). Different lengths are worn for different occasions and different outfits. The most common length is the 18" length, which typically falls at the collarbone. 16": Choker length. Accentuates her neckline. 18": At collarbone. Classic length. 20": A few inches below collarbone. 22": At or above neckline. For more dramatic, stylish look.

For US orders, Brilliant Earth currently only collects sales tax on orders shipped to addresses in California State. For orders shipped to Canada, the UK, or Australia, Brilliant Earth collects the relevant GST/PST/HST/VAT based on the country/province that the order is being shipped to. There are no additional duties for orders shipped to Canada, or Australia. For orders shipped to the UK, Brilliant Earth collects the relevant duties for each order. Taxes and duties on orders will be calculated based on the rates in effect the date your order ships.

Blockchain technology is revolutionizing the natural diamond industry. Our blockchain keeps track of every step in a diamond’s journey – from mining, to market, to the moment it reaches you – safely, securely, and permanently. With our blockchain-enabled diamonds, you’ll have an enduring digital record about where your diamond comes from and how it was sourced. In 2019, we became one of the first retailers to offer blockchain-enabled diamonds, and year after year we have increased our offering of blockchain-enabled diamonds, ahead of our ESG Goals.

For a collection of diamonds, Brilliant Earth includes the GIA Diamond Origin Report to help trace the diamond from its source to its final polished state by uniquely leveraging advanced scientific analysis to deliver technical rough-to-polish diamond matching. GIA collects and analyzes physical measurements, spectroscopic data, and imaging of the diamond as a rough crystal before it is cut and polished. A unique identification number is assigned to the rough diamond. GIA later uses this data to scientifically match the polished diamond to the original rough crystal it came from.

Hearts and Arrows diamonds are highly coveted because they’re cut with high precision and exceptional craftsmanship. These round brilliant diamonds are cut to proper proportions and crafted with a high degree of facet precision to exhibit a sharp pattern of eight arrows in the face up view and eight small hearts from the pavilion. The cut grade of hearts and arrows is evaluated by its facets appearance - exhibiting excellent face-up appearance with brightness, scintillation, and fire.

The type of accent diamonds in this engagement ring setting will match the type of your selected center diamond. If a natural center diamond is selected, then the accent diamonds will be natural diamonds. If a lab grown center diamond is selected for this setting, then the accent diamonds will be lab grown.

Brilliant Earth goes above and beyond the current industry standards to offer Beyond Conflict Free Diamonds^TM with a listed origin of Canada or Botswana Sort.

Botswana Sort diamonds are sourced from mines with strong social and environmental governance practices in Botswana, Namibia, South Africa, and Canada, all ranked low to moderate risk.

Our Pathway to Beyond Conflict Free™ diamonds are sourced from Angola, a country known for natural diamonds of exceptional quality. Through growing investment in sustainable practices, Angola is actively working towards more responsible mining.