At ith, we strive to create an experience that allows our customers to fully appreciate the value and allure of diamonds and to encounter diamonds that are unique to them, since this is a once-in-a-lifetime wedding occasion.
Among the 4C diamond evaluation criteria, carat weight and cut are the most important elements in bridal ring design, and our diamonds are designed with a balance of rarity and diversity in mind.

The Diamond Selecting for the Two of You

At ith, we do not operate as a sales business,
but rather, in order to ensure that our customers purchase what is right for them,
we do not carry more inventory than necessary,
and we work with multiple jewelers to purchase the best diamonds for each customer's needs.
ith's philosophy of putting your preference first that is also reflected in the diamond selecting of ith.

Engagement Rings Diamonds with Certificates

The diamonds of an engagement ring gives the shape to the wearers' wishes and the affection of the one who gave it.
In addition to size and quality, the first glance and feeling of the diamonds are also important.
No two pieces of diamonds are the same, and the once-in-a-lifetime encounter with it enhances the special meaning of the ring.
The one and only diamond with the special ring design creates a unique ring that is just for the two of you. Proudly crafted in Japan, for loving couples in Singapore.

Made-to-Order of Engagement Rings

For you who like to be even more particular about your engagement ring, we recommend made-to-order engagement rings.
Even with the same ring design, the impression of the ring can change dramatically when the size or shape of the diamond changes.
We offer a wide range of consultation services, from semi-custom-made orders to full custom-made orders, in order to fulfill the ideal design you have in mind or the compatibility with your wedding rings.
Please feel free to contact us regarding your budget or desired diamond grade.

Wedding Rings Melee Diamonds without Certificates

Even the melee diamonds without certificates, we still select them in particular for their quality.
The melee diamonds we used in ring making are color equivalent to F color (colorless) and clarity around VS class (very few inclusions).
As for the diamond cut grade, you can also choose H&A (Hearts & Arrows) diamonds.

Eternity Rings

The eternity rings, with the name meaning eternity, are designed to symbolise eternal love with the uninterrupted row of diamonds.
The key to the eternity ring style is a neat row of diamonds of the same size.
By unifying the size or color, the beauty of this ring design is accentuated.
Our in-house artisans, who are particular about aesthetics and craftsmanship, will select and set each melee diamond on a ring one by one.

Diamond Search

At ith's atelier, you can view the actual loose diamonds and choose the size, brilliance, and budget that best suits your needs.

Grading Report

The following standards apply to diamonds handled by ith. A certificate of domestic grading organization is available upon request.

Carat 0.2ct〜 ※Except for Fancy Cut Diamonds
Cut Excellent
Color D~H
Clarity IF~VS

ith Diamonds

"ith Diamonds" is ith's special program that provides customers with two pieces of diamonds cut from the same rough diamond. A single rough diamond is cut into a pair of diamonds to create the unique wedding rings for you and your partner.

The "ith Diamonds" initiative also emphasizes traceability, collects and stores all the datas of each diamond, start from Kimberley Process Certificate, a certificate of origin that identifies each diamond, as well as photographs of rough diamonds and Sarine Profile™, the detailed report of the diamond including design images used to cut diamonds from rough diamonds. Through these processes, we have prepared a system that traces the diamonds delivered to our customers from the place of production, through processing, to sales and distribution. Customers who choose "ith Diamonds" will be issued with an ith original certificate as proof of having gone through these processes.

4C The Diamond 4Cs

The diamond 4Cs are derived from the initial letters of the four categories used to evaluate a round brilliant cut diamond.
The 4Cs are: Carat(weight), Color(shade), Clarity(transparency), and Cut(brilliance).
This standard was proposed by the GIA (Gemological Institute of America) in the mid-20th century.
By establishing clear indicators for the evaluation of diamonds, which until then had been left to the subjective judgment of jewelers, a common understanding of the objective evaluation of individual diamonds was created.
Until these days, the diamond 4Cs are accepted around the world, and well-known high jewelers also use the diamond 4Cs to evaluate diamonds.


  • 6.5mm 1.00ct
  • 5.8mm 0.70ct
  • 5.1mm 0.50ct
  • 4.8mm 0.40ct
  • 4.3mm 0.30ct
  • 3.8mm 0.20ct
  • 3.0mm 0.10ct

Although often thought of as a unit of size,carats are a unit of weight for gemstones,
with one carat weighing 0.2 grams.
It is said to derive from the Greek word "Kararation," which means locust bean,
since in ancient times locust beans (carob beans) were used as weights to weigh gemstones.


  • D, E, F Colorless
  • G, H, I, J Near Colorless
  • K, L, M Faint Yellow
  • N, O, P, Q, R Very Light Yellow
  • S, T, U, V, W, X, Y, Z Light Yellow

Diamonds are often slightly yellowish with nitrogen,
and the closer to pure colorless transparency, the rarer and more valuable they are.
The color rating is divided into 23 alphabetical grades, from the highest grade D, to the lowest grade Z.


  • FL/IF Without inclusions
  • VVS1/VVS2 Inclusions that are very difficult to detect
  • VS1/VS2 Difficult-to-find inclusions
  • SI1/SI2 Easy to detect, difficult to see with the naked eye
  • I1/I2/I3 Easily detectable with the naked eye.

Clarity indicates the clarity of the diamond, which is evaluated by observing it with a 10x magnification loupe
and comprehensively evaluating the size, number, location, quality, color and prominence of inclusions,
as well as any abrasions or scratches that occurred after the cutting process.
Grades are divided into 11 grades, from "FL (flawless)" with no scratches or defects at all,
to those with inclusions visible to the naked eye.


  • Excellent
  • Very Good
  • Good
  • Fair
  • Poor

Cut is the only element in which humans can be involved in the evaluation of a diamond.
The diamond is graded on a five-point scale based on ideal proportion, with the beauty of the polishing, technical cutting skill, and other factors being evaluated using a subtractive point system.
We can select the diamonds that best suit your tastes and preferences, or you may select the diamonds yourself.
A certificate of authenticity will be included with the diamond.
We offer a variety of diamonds to suit all budgets.

Triple Excellent

A diamond's cut grade is based on three factors: proportion (shape), polish (polish condition), and symmetry. Triple Excellent diamonds are diamonds that have been cut with the highest degree of precision and have received the highest rating of "Excellent" for all three elements. Because ith is a brand started by an artisan, we do not compromise but use only the finest diamonds cut by the skillful diamond cutters.

Hearts & Arrows

Among round brilliant cut diamonds, those that are finished with a certain level of symmetry show a pattern of eight arrows on the table side and eight heart marks on the culet side when viewed through a special scope. Diamonds that produce this pattern are called "Hearts and Arrows" (H&A), and are one indicator of a diamond cutter’s high level skill.
At ith, we also offer a special diamond called the Perfect H&A (Hearts and Arrows), which is evaluated from our own perspective. H&A is certified by domestic grading organizations in Japan, but there is a wide range of tolerance in the expression of patterns and considerable individual variation.

ith's Conditions of a Perfect H&A Diamond

When looking through a scope, all eight hearts and arrows appear immediately. No matter how many times you look through a scope, there will always be hearts and arrows without missing one piece. The shape of the pattern should be easily identified as hearts and arrows(in the case of arrows, ones with big arrowheads and short shafts will be inspected as a beautiful shape of arrows).

Shape The Shape of Diamonds

When we talk about diamonds, we usually mean round brilliant cut diamonds.
However, there are a wide variety of diamond/gemstone cuttings.
At ith, we take orders with the diamond shape of your choice.
You may express yourself through the shape of the gemstone.
From princess cut diamonds to hearts or marquises.
Please choose one according to your own preference

Propose Propose with a Diamond

For you, who want to propose to your partner with an engagement ring, yet don’t know the ring size.
To propose with a diamond may be the answer to such a problem.
By doing so, you may take your time to choose the ring design after the proposal has been successfully made.
The diamond proposal might be the ideal way for both of you.