Custom Cut Diamonds: How a Diamond Is Cut to Your Spec

In this guide

    By Clint Casmiro, Co-Founder, Smiro Studio, Toronto · Updated September 27, 2026

    Short answer: A custom cut diamond is cut from rough to your numbers: shape, proportions, facet pattern, sometimes colour. We describe the stone with you, source rough that can become it, have a master cutter shape it while you approve along the way, then send it to IGI for independent grading. It takes longer than buying from stock and the result is one of one.

    The open market is finite. Sometimes the exact stone in your head does not exist yet. That is when we cut one.

    How does custom cutting work?

    1. We talk it through. Shape, colour, proportions, the feeling you are after.
    2. We source the rough. We find rough that can actually become that stone and show you what is possible first.
    3. It gets cut to spec. A master cutter shapes it to your numbers and you approve along the way.
    4. IGI certifies it. The finished stone goes to IGI for independent grading and its own certificate.

    What can be custom cut?

    Unusual outlines like shield, kite, lozenge, coffin, octagon, hybrid cushion-oval, and fully custom silhouettes like a letter, a butterfly or a cross. Specific ratios, like a 2.0 moval. And facet patterns like Portuguese, old mine or crisscut.

    How long does a custom cut add?

    It adds time on top of the normal 10 to 14 week build, because cutting starts before the ring design is final. We give you a realistic date on the call once we know the stone.

    When should I not custom cut?

    When a stock stone already gets you 95 percent there. We look through hundreds of stones first. Custom cutting is for when nothing fits.

    Want us to look at your idea?

    A free 30 minute video call with Clint or Karina. Bring a photo, a budget, or nothing at all.

    Book a free callSee our process

    Questions we get about this

    Can you cut a diamond from scratch?

    Yes. We source the rough and have it cut to your spec, then IGI grades it and issues a certificate.

    Is a custom cut diamond lab grown or natural?

    Either. We work with lab grown and natural rough.

    Will a custom cut diamond have a certificate?

    Yes. Every finished custom cut stone goes to IGI for independent grading.

    What shapes can you custom cut?

    Shield, kite, lozenge, coffin, octagon, hybrid cushion-oval, and custom silhouettes like a letter or a butterfly.

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    Rings we have made for couples

    Moval-Cut Diamond Ring with Tulip Petals

    Moval-Cut Diamond Ring with Tulip Petals

    A 2.05ct moval in a 6 petal east west tulip setting, platinum, with a hand engraved north star beneath the bridge. From Sam's sketch to the finished ring.
    Old Mine Cushion Diamond Ring

    Old Mine Cushion Diamond Ring

    A 2.5ct old mine cushion, newly cut in the antique style, set in 14k yellow gold with a hidden halo and low profile basket. Why Simon asked for an old mine by name, and how we built it.

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