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    Loose SI1 (Slightly Included) Diamonds

    SI1 (Slightly Included 1) diamonds represent an exceptional value proposition, with inclusions typically invisible to the naked eye despite being identifiable under 10x magnification. Our Antwerp collection features these carefully selected gems where strategic positioning of natural characteristics preserves exceptional brilliance and fire, offering collectors the perfect balance between visual appeal and investment wisdom.

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    Fancy color

    Fancy color

    Fancy colored diamonds are incredibly rare and fascinating. Nearly every color you can think of is available in fancy color diamonds. There are a huge variety of beautiful color options. Pink, blue, green, brown diamonds look charming and mesmerizing.

    LEARN ABOUT DIAMOND FANCY COLOR
    Intensity

    Intensity

    Diamond intensity refers to the strength or saturation of a fancy color diamond’s hue. It’s a key factor in determining a diamond’s value and desirability.

    LEARN MORE ABOUT Intensity
    Overtone

    Overtone

    Diamond overtone is a subtle, secondary color that can be observed in some fancy color diamonds, particularly those with intense or vivid hues. It’s like a whisper of color layered over the primary color, adding depth and complexity to the diamond’s brilliance.

    LEARN MORE ABOUT Overtone
    Shape

    Shape

    Diamond shape refers to the overall outline and facets of a diamond. It’s a crucial factor that affects a diamond’s brilliance, fire, and scintillation – its ability to reflect light and sparkle.

    LEARN MORE ABOUT Shape
    Clarity

    Clarity

    Diamond clarity refers to the absence of inclusions (internal flaws) and blemishes (external imperfections) within a diamond. It’s one of the four Cs (carat, cut, clarity, and color) that determine a diamond’s value and price.

    LEARN MORE ABOUT Clarity
    Carat weight

    Carat weight

    Diamond weight, also known as carat weight, is a measure of a diamond’s mass. It’s one of the four Cs (carat, cut, clarity, and color) that determine a diamond’s value and price.

    LEARN MORE ABOUT DIAMOND CARAT
    Price

    Price

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    0.32 Ct Fancy Vivid Yellow Cushion Modified Brilliant Natural Diamond

    0.32 Ct Fancy Vivid Yellow Cushion Modified Brilliant Natural Diamond

    Price Upon Request
    0.50 Ct Fancy Deep Brownish Yellow Cushion Modified Brilliant Natural Diamond

    0.50 Ct Fancy Deep Brownish Yellow Cushion Modified Brilliant Natural Diamond

    Price Upon Request
    0.52 Ct Fancy Vivid Orangy Yellow Cushion Modified Brilliant Natural Diamond

    0.52 Ct Fancy Vivid Orangy Yellow Cushion Modified Brilliant Natural Diamond

    Price Upon Request
    0.66 Ct Fancy Light Brownish Pink Cushion Modified Brilliant Natural Diamond

    0.66 Ct Fancy Light Brownish Pink Cushion Modified Brilliant Natural Diamond

    3,500.00$
    2.79 Carat Fancy Intense Green Cushion Modified Brilliant SI1 Diamond GIA

    2.79 Carat Fancy Intense Green Cushion Modified Brilliant SI1 Diamond GIA

    880,000.00$
    0.62 Carat Fancy Green Cushion Modified Brilliant SI1 Diamond GIA

    0.62 Carat Fancy Green Cushion Modified Brilliant SI1 Diamond GIA

    33,480.00$
    1.02 Carat O-P Cushion Shape SI1 Diamond GIA

    1.02 Carat O-P Cushion Shape SI1 Diamond GIA

    1,650.00$
    1.01 Carat U-V Cushion Shape SI1 Diamond GIA

    1.01 Carat U-V Cushion Shape SI1 Diamond GIA

    1,700.00$
    1.37 and 1.53 carat Pair of F / G SI1 Shield Shape Diamonds

    1.37 and 1.53 carat Pair of F / G SI1 Shield Shape Diamonds

    19,500.00$
    1.01 carat Fancy Deep Brownish Greenish Yellow SI1 Round Shape Diamond GIA

    1.01 carat Fancy Deep Brownish Greenish Yellow SI1 Round Shape Diamond GIA

    5,950.00$
    4.24 carat Fancy Deep Brownish Yellowish Orange SI1 Emerald Shape Diamond GIA

    4.24 carat Fancy Deep Brownish Yellowish Orange SI1 Emerald Shape Diamond GIA

    39,008.00$
    3.05 carat Fancy Light Brownish Greenish Yellow SI1 Pear Shape Diamond GIA

    3.05 carat Fancy Light Brownish Greenish Yellow SI1 Pear Shape Diamond GIA

    10,235.00$
    0.51 carat Fancy Brownish Orangy Pink SI1 Cushion Shape Diamond GIA

    0.51 carat Fancy Brownish Orangy Pink SI1 Cushion Shape Diamond GIA

    Item Upon Request
    5.08 carat Fancy Brownish Greenish Yellow SI1 Radiant Shape Diamond GIA

    5.08 carat Fancy Brownish Greenish Yellow SI1 Radiant Shape Diamond GIA

    Item Upon Request
    1.00 carat L SI1 Pear Shape Diamond GIA

    1.00 carat L SI1 Pear Shape Diamond GIA

    Item Upon Request
    1.00 carat L SI1 Pear Shape Diamond GIA

    1.00 carat L SI1 Pear Shape Diamond GIA

    Item Upon Request
    1.53 carat Light Yellow (U-V) SI1 Radiant Shape Diamond GIA

    1.53 carat Light Yellow (U-V) SI1 Radiant Shape Diamond GIA

    Item Upon Request
    1.04 carat Fancy Yellow SI1 Radiant Shape Diamond GIA

    1.04 carat Fancy Yellow SI1 Radiant Shape Diamond GIA

    Item Upon Request
    1.55 carat Fancy Intense Yellow SI1 Radiant Shape Diamond GIA

    1.55 carat Fancy Intense Yellow SI1 Radiant Shape Diamond GIA

    Item Upon Request
    2.07 carat L SI1 Pear Shape Diamond HRD

    2.07 carat L SI1 Pear Shape Diamond HRD

    Item Upon Request
    1.01 carat E SI1 Round Shape Diamond GIA

    1.01 carat E SI1 Round Shape Diamond GIA

    Item Upon Request
    1.02 carat Fancy Yellow VS1 Cushion Shape Diamond GIA

    1.02 carat Fancy Yellow VS1 Cushion Shape Diamond GIA

    Item Upon Request
    0.70 carat Very Light Green SI1 Cushion Shape Diamond GIA

    0.70 carat Very Light Green SI1 Cushion Shape Diamond GIA

    Item Upon Request
    2.66 carat Fancy Deep Yellow SI1 Round Shape Diamond GIA

    2.66 carat Fancy Deep Yellow SI1 Round Shape Diamond GIA

    Item Upon Request
    0.19 carat Very Light Pink SI1 Cushion Shape Diamond GIA

    0.19 carat Very Light Pink SI1 Cushion Shape Diamond GIA

    Item Upon Request
    0.90 carat Light Pinkish Brown SI1 Round Shape Diamond GIA

    0.90 carat Light Pinkish Brown SI1 Round Shape Diamond GIA

    Item Upon Request
    0.45 carat Fancy Brownish Purplish Pink SI1 Radiant Shape Diamond GIA

    0.45 carat Fancy Brownish Purplish Pink SI1 Radiant Shape Diamond GIA

    Item Upon Request
    0.47 carat Fancy Green Yellow SI1 Radiant Shape Diamond GIA

    0.47 carat Fancy Green Yellow SI1 Radiant Shape Diamond GIA

    Item Upon Request
    0.91 carat Fancy Grayish Yellowish Green SI1 Cushion Shape Diamond GIA

    0.91 carat Fancy Grayish Yellowish Green SI1 Cushion Shape Diamond GIA

    Item Upon Request
    1.04 carat Fancy Light Greenish Yellow SI1 Radiant Shape Dimond GIA

    1.04 carat Fancy Light Greenish Yellow SI1 Radiant Shape Dimond GIA

    Item Upon Request
    3.07 and 3.25 carat Pair of J/H SI1 Triangle Shape Dimonds GIA

    3.07 and 3.25 carat Pair of J/H SI1 Triangle Shape Dimonds GIA

    Item Upon Request
    1.04, 0.90 and 1.01 carat Triple Set of Fancy Light Green, Fancy Orangy Pink and Fancy Intense Green-Yellow Pear Shape Diamonds GIA

    1.04, 0.90 and 1.01 carat Triple Set of Fancy Light Green, Fancy Orangy Pink and Fancy Intense Green-Yellow Pear Shape Diamonds GIA

    Item Upon Request
    6.10 carat Light Yellow (W-X) SI1 Cushion Shape Diamond IGI

    6.10 carat Light Yellow (W-X) SI1 Cushion Shape Diamond IGI

    Item Upon Request
    1.01 carat G SI1 Heart Shape Diamond HRD

    1.01 carat G SI1 Heart Shape Diamond HRD

    Item Upon Request
    4.01 carat Fancy Deep Yellow SI1 Emerald Shape Diamond GIA

    4.01 carat Fancy Deep Yellow SI1 Emerald Shape Diamond GIA

    Item Upon Request
    1.33 carat Fancy Blue Green SI1 Radiant Shape Diamond GIA

    1.33 carat Fancy Blue Green SI1 Radiant Shape Diamond GIA

    Item Upon Request
    10.02 Carat Fancy Brownish Yellow SI1 Radiant Shape Diamond GIA

    10.02 Carat Fancy Brownish Yellow SI1 Radiant Shape Diamond GIA

    Item Upon Request
    1.00 carat Fancy Vivid Yellowish Orange SI1 Cushion Shape Diamond GIA

    1.00 carat Fancy Vivid Yellowish Orange SI1 Cushion Shape Diamond GIA

    Item Upon Request
    1.00 carat I SI1 Round Shape Diamond HRD

    1.00 carat I SI1 Round Shape Diamond HRD

    Item Upon Request
    0.30 carat Fancy Intense Pink SI1 Radiant Shape Diamond GIA

    0.30 carat Fancy Intense Pink SI1 Radiant Shape Diamond GIA

    Item Upon Request
    0.25 and 0.23 carat Pair of Fancy Intense Blue VS2/SI1 Radiant Shape Diamond GIA

    0.25 and 0.23 carat Pair of Fancy Intense Blue VS2/SI1 Radiant Shape Diamond GIA

    Item Upon Request
    0.58 carat Fancy Vivid Yellow SI1 Round Shape Diamond GIA

    0.58 carat Fancy Vivid Yellow SI1 Round Shape Diamond GIA

    Item Upon Request
    0.80 and 0.80 carat Pair of Fancy Vivid Yellow, Fancy Deep Yellow VS2, SI1 Round Shape Diamonds GIA

    0.80 and 0.80 carat Pair of Fancy Vivid Yellow, Fancy Deep Yellow VS2, SI1 Round Shape Diamonds GIA

    Item Upon Request
    1.68 carat Fancy Vivid Orangy Yellow SI1 Heart Shape Diamond GIA

    1.68 carat Fancy Vivid Orangy Yellow SI1 Heart Shape Diamond GIA

    Item Upon Request
    1.01 carat Yellow (Y-Z) SI1 Round Shape Diamond GIA

    1.01 carat Yellow (Y-Z) SI1 Round Shape Diamond GIA

    Item Upon Request
    1.03 and 1.00 carat Pair of Faint Grey SI1 Round Shape Diamonds GIA

    1.03 and 1.00 carat Pair of Faint Grey SI1 Round Shape Diamonds GIA

    Item Upon Request

    Frequently Asked Questions

    Are SI1 diamonds visibly included to the naked eye?

    SI1 (Slightly Included 1) diamonds occupy a transitional position on the clarity scale—some appear completely eye-clean while others show minor visible characteristics depending on inclusion type and placement. Approximately 70% of SI1 diamonds appear clean to the average observer without magnification, particularly in smaller sizes and brilliant cuts. When selecting these natural gems, prioritize stones with inclusions positioned under facet junctions or near edges rather than centered under the table. For value-conscious collectors, carefully selected SI1 diamonds can offer exceptional value, delivering visually clean appearance in conflict-free stones at 30-40% below the cost of comparable VS2 diamonds.

    What types of inclusions are common in SI1 diamonds?

    SI1 diamonds typically contain crystalline inclusions, small feathers, clouds, or needle formations visible under standard magnification. The defining characteristic of this clarity grade involves inclusions that are noticeable to a trained gemologist within seconds under 10x magnification but may remain invisible to the naked eye depending on their nature and position. White or transparent inclusions generally remain less visible than dark or reflective ones in these natural stones. For purchasers seeking value in precious gems, carefully selected SI1 diamonds with strategic inclusion placement can represent excellent cost-to-quality ratio, particularly in brilliant cuts where faceting naturally disguises minor characteristics.

    How does diamond shape affect the visibility of SI1 inclusions?

    Diamond shape significantly impacts inclusion visibility in SI1 clarity stones, with brilliant cuts like round, princess, and radiant naturally masking characteristics through their complex faceting patterns. Conversely, step-cut shapes such as emerald and Asscher, with their long, transparent facets, tend to reveal SI1 inclusions more readily in these natural gems. Oval and pear shapes may show “bow-tie” effects that interact with inclusions, either hiding or highlighting them depending on placement. For maximum value in conflict-free diamonds, consider brilliant cuts in SI1 clarity, as they frequently appear eye-clean while offering substantial savings compared to higher clarity grades.

    Are SI1 diamonds a good value proposition?

    SI1 diamonds often represent an excellent value for budget-conscious collectors when carefully selected for eye-cleanliness and proper inclusion placement. These natural stones typically cost 30-40% less than comparable VS2 diamonds while potentially delivering identical visible appearance. The key lies in selective purchasing—examining each stone individually or reviewing detailed inclusion plots to verify that characteristics won’t impact beauty. For buyers prioritizing maximum carat weight and visual impact over technical specifications, selectively chosen SI1 diamonds in brilliant cuts offer perhaps the strongest value proposition in the market, delivering the appearance of higher clarity at significantly lower cost per carat.

    We Educate

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    Bringing clarity to the realm of diamonds, gems, and fine jewelry through insight that elevates interest into true expertise.

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    More About Loose Diamonds at Reuven Veksler

    Understanding Diamond Quality and Certification

    Evaluating loose diamonds requires comprehensive knowledge of the 4Cs and certification standards that determine both aesthetic appeal and investment potential. Cut precision directly impacts light refraction and exceptional brilliance, while color grading reveals the stone’s optical purity on the D-Z scale. Professional gemological evaluation from laboratories like GIA or IGI provides authentication of natural origin, ensuring buyers receive conflict-free diamonds with documented quality characteristics rather than synthetic alternatives.

    Read more +

    Investment Advantages of Loose Diamond Purchasing

    Investment-grade loose diamonds offer significant cost-per-carat advantages over pre-set jewelry, allowing buyers to assess clarity characteristics without setting interference. The loose diamond market provides direct access to collector-grade specimens, eliminating multiple retail intermediaries that typically increase final pricing. When you buy loose diamonds online with proper certification, traceable origins ensure transparency about the stone’s journey from mine to market, protecting your investment through verified provenance documentation.

    Reuven Veksler’s Premium Natural Diamond Collection

    Hand-picked from our exclusive Antwerp vault, Reuven Veksler’s premium collection represents five decades of gemological expertise and artisan craftsmanship. As certified members of the Antwerp Diamond Exchange since 1974, we provide direct access to museum-quality natural diamonds with sustainable sourcing practices and lifetime warranty protection. Our conflict-free stones undergo rigorous evaluation to ensure exceptional brilliance and authentic value, offering bespoke jewelry creation opportunities and superior investment potential for discerning collectors worldwide.

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    Frequently Asked questions

    Why should I buy loose diamonds instead of pre-mounted stones? 

    Buying loose diamonds allows you to examine the stone’s natural characteristics without interference from settings, ensuring you purchase genuine, high-quality specimens. You can verify the diamond’s clarity, color grade, and cut quality independently, often achieving better value and cost efficiency. Loose stones also provide flexibility for custom jewelry creation, where you control both the diamond selection and setting design process.

    What certifications should I look for when purchasing diamonds? 

    GIA certified diamonds represent the gold standard in gemological evaluation, providing detailed analysis of cut, clarity, color, and carat weight. Other reputable certifications include IGI and HRD, particularly for stones originating from Antwerp’s diamond exchanges. These certificates document the diamond’s natural origin, conflict-free status, and authentic characteristics, protecting your investment and ensuring genuine quality.

    What are conflict-free diamonds and why choose them? 

    Conflict-free diamonds are ethically sourced stones that were not mined in areas where proceeds funded armed conflict or human rights abuses. These natural diamonds with clear, traceable origins represent a responsible choice for buyers who want their purchase to reflect their values. At Reuven Veksler, we deal exclusively with conflict-free diamonds that come with proper certifications from reputable laboratories like GIA, ensuring both genuine quality and peace of mind for your investment.

    Where should I buy certified loose diamonds for the best value? 

    When purchasing certified loose diamonds, choose reputable dealers who provide comprehensive documentation and ethical sourcing guarantees. Ensure each stone comes with certification from respected laboratories like GIA, AGS, or IGI to verify authenticity and quality. At Reuven Veksler, we offer conflict-free diamonds with lifetime warranties, complete provenance documentation, and expert guidance to make your diamond buying experience both secure and valuable, whether you’re seeking investment-grade stones or creating bespoke jewelry.

    We Educate

    View more

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    • Lifestyle
    What to Do in Antwerp: Culture, Cuisine, and Diamonds

    Antwerp is a city that reveals itself gradually. It is not loud, not theatrical, and not designed for mass tourism. Instead, it offers depth: centuries of trade and craftsmanship, serious…

    BySarah Veksler
    January 28, 2026
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    • Jewelry
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    The landscape of luxury jewelry is transforming as we move through 2026. After several years dominated by delicate “quiet luxury” pieces, a clear shift is underway toward bolder styles and…

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    January 20, 2026