Fab Diamond Guide: Every Type of Fake Diamond & Diamond Simulant Explained (2026)
Last Updated: March 18, 2026
Quick Answer: What Is a Fab Diamond?
A fab diamond — short for fabricated or faux diamond — is any gemstone or material engineered to look like a natural diamond without sharing its geological origin. The most popular fab diamond types include moissanite, cubic zirconia (CZ), white sapphire, white topaz, and lab-created diamonds. Of these, only lab-grown diamonds are chemically, physically, and optically identical to mined diamonds; all others are true diamond simulants — beautiful in their own right, but distinct in composition.
At Riona Jewel, we specialize in GIA- and IGI-certified lab-grown diamonds that deliver the same brilliance, fire, and scintillation as mined stones — at up to 85% less cost, with zero conflict and a significantly smaller carbon footprint. Browse our full collection of lab-grown diamond engagement ring.
Table of Contents
- What Is a Diamond Simulant? Understanding Faux & Fake Diamonds
- The 8 Main Types of Diamond Simulants Compared
- Lab-Created Diamond vs. Diamond Simulant: The Critical Difference
- Shop Riona Jewel Lab-Grown Diamond Rings
- How to Choose the Right Diamond Alternative: Step-by-Step
- Mined Diamond vs. Lab-Grown Diamond vs. Moissanite: Full Comparison
- Shop by Style: Our Most-Loved Engagement Ring Designs
- Your Complete Diamond Simulant Buyer's Checklist
- Frequently Asked Questions
What Is a Diamond Simulant? Understanding Faux & Fake Diamonds
Walk into any jewelry store — or scroll through Instagram — and you will encounter dozens of rings described as diamond look-alikes, diamond alternatives, or simply faux diamonds. The terminology can be confusing, and that confusion often costs buyers money or leads to disappointment when a stone doesn't perform as expected. As GIA-certified gemologists who have helped over 2,000 couples choose the right stone, we believe clarity is the greatest luxury we can offer.
The broad umbrella term diamond simulant covers every gemstone, material, or lab-engineered crystal that visually resembles a diamond without actually being one — whether mined or lab-created. A simulated diamond mimics the appearance of a diamond but differs fundamentally in chemical composition, refractive index, hardness, and often in brilliance and fire. The term imitation diamond is commonly used interchangeably, though many gemologists reserve it specifically for materials that are entirely transparent and colourless but share none of diamond's unique properties.
A fake diamond — in the strictest sense — is any stone presented or sold as a real diamond when it is not. Crucially, there is nothing inherently deceptive about a diamond simulant when it is accurately labelled. Many couples deliberately choose a diamond substitute for budget, ethical, or aesthetic reasons, and do so with full knowledge of what they are purchasing. Understanding the distinction between a diamond simulant and a lab-created diamond is the most important piece of education we can give you before you shop.
The global market for diamond alternatives has expanded dramatically since 2020. Searches for "moissanite engagement ring" increased by over 300% between 2019 and 2024, according to Google Trends data. Simultaneously, lab-grown diamond adoption has surged — with IGI-certified lab diamonds now accounting for more than 61% of all engagement ring center stones sold in the United States. Whether you are drawn to a fab diamond for its price point, its ethics, or its unique optical character, this guide will ensure you choose with confidence.
The 8 Main Types of Diamond Simulants — Faux Diamonds Ranked
Not all fake diamonds are equal. Each diamond imitation material has distinct optical, physical, and durability properties that make it suited to different budgets and lifestyles. Below is a gemologist's honest breakdown of every major type of diamond look-alike on the market in 2026, ranked from most diamond-like to least.
1. Lab-Created Diamond (CVD & HPHT)
Despite often being grouped with diamond simulants in popular conversation, a lab-created diamond is not a simulant at all — it is a real diamond. CVD (Chemical Vapour Deposition) and HPHT (High Pressure High Temperature) are the two production methods. Both result in pure carbon crystals with the same hardness (10 on the Mohs scale), the same refractive index (2.417), and identical chemical composition as a mined diamond. A GIA or IGI grading report certifies these stones to the exact same 4Cs standards. We cover this distinction in detail in the section below, but if your priority is owning a real diamond — just conflict-free and more affordable — a lab-grown diamond is your answer.
2. Moissanite
Discovered in 1893 by Henri Moissan inside a meteor crater, moissanite is silicon carbide (SiC) — a naturally rare mineral now produced in laboratories for jewellery use. Of all true diamond simulants, moissanite is the closest in appearance and durability. It scores 9.25 on the Mohs hardness scale, making it the second hardest gemstone used in jewellery. Its refractive index (2.65–2.69) is actually higher than diamond's, which means moissanite disperses more coloured light — a visual effect that many people love but that a trained gemologist will immediately identify as "too much rainbow flash." A well-cut moissanite in a solitaire setting is a genuinely breathtaking stone.
3. Cubic Zirconia (CZ)
Cubic zirconia is the most widely sold fake diamond on the market by volume — and one of the most misunderstood. Chemically it is zirconium dioxide (ZrO₂), synthesised in laboratories since the 1970s. CZ is considerably softer (8–8.5 Mohs), less dense than diamond, and over time it scratches, clouds, and loses its lustre. A brand-new CZ is visually convincing, but even a trained eye can spot the difference — CZ lacks diamond's adamantine lustre and displays a different type of fire. For fashion jewellery or pieces worn occasionally, CZ is a reasonable diamond alternative. For an engagement ring worn daily, it is not recommended without accepting frequent replacement.
4. White Sapphire
White sapphire (aluminium oxide, Al₂O₃) is a corundum mineral that scores 9 on the Mohs scale — highly durable for everyday wear. Unlike diamond or moissanite, white sapphire has a low refractive index and minimal dispersion, which gives it a "glassy" or "milky" appearance rather than the scintillating brilliance associated with diamonds. It is a genuinely beautiful stone in its own right, but if you are specifically seeking a simulated diamond with diamond-like sparkle, white sapphire will likely disappoint. It performs best in vintage and art-deco inspired settings where its subtle lustre complements the overall design.
5. White Topaz
White topaz (Al₂SiO₄(F,OH)₂) scores 8 on the Mohs scale and has a refractive index of 1.609–1.643 — substantially lower than diamond. It is affordable and initially clear, but its relatively low hardness means it is prone to scratching and will appear dull after regular wear. Like white sapphire, it lacks the fire and brilliance that people associate with a diamond look-alike. White topaz is best suited to pendants or earrings rather than rings subject to daily abrasion.
6. Morganite & Aquamarine
These coloured beryl varieties are sometimes promoted as diamond alternatives for couples who prefer coloured stones. Morganite's blush-pink hue and aquamarine's sea-blue colour make them poor visual substitutes for colourless diamonds, but they are increasingly fashionable as centre stones in their own right. Both score 7.5–8 on the Mohs scale. They are not strictly diamond simulants — they are simply beautiful coloured gemstones chosen as a conscious diamond substitute for artistic reasons.
7. Rhinestone & Crystal (Swarovski)
Rhinestones are cut glass or crystal with a reflective metal foil backing. Swarovski crystals are precision-cut lead glass with proprietary coatings. Both create impressive sparkle in fashion jewellery but score only 6–7 on the Mohs scale and have none of diamond's optical properties. They are entirely appropriate for fashion accessories and costume jewellery but should never be set in a fine ring intended for long-term wear.
8. Glass & Synthetic Garnet (YAG)
Yttrium aluminium garnet (YAG) and gadolinium gallium garnet (GGG) were early synthetic diamond simulants used before moissanite and CZ became widely available. They remain the least convincing imitation diamond options, with low hardness (8.5 for YAG) and a greasy lustre. Plain glass — occasionally set into very low-cost jewellery — is the least diamond-like material of all, with a hardness of just 5–6 and a flat, lifeless appearance under light.
At a Glance: Diamond Simulant Quick Reference
- Lab-Grown DiamondCarbon (C) · Mohs 10 · RI 2.417 · Real diamond ✔
- MoissaniteSilicon Carbide (SiC) · Mohs 9.25 · RI 2.65–2.69
- Cubic ZirconiaZirconium Dioxide (ZrO₂) · Mohs 8–8.5 · RI 2.15–2.18
- White SapphireAluminium Oxide (Al₂O₃) · Mohs 9 · RI 1.762–1.770
- White TopazAluminium Silicate · Mohs 8 · RI 1.609–1.643
- Glass / RhinestoneSiO₂ (glass) · Mohs 5–6 · Not recommended for rings
Lab-Created Diamond vs. Diamond Simulant: The Critical Difference
This is the question we answer most often at Riona Jewel, and it is worth stating clearly: a lab-grown diamond is not a diamond simulant. It is a real diamond. The Federal Trade Commission (FTC) has explicitly stated that the definition of "diamond" does not require the stone to be mined from the earth — it requires only that the stone be composed of pure carbon in a cubic crystal structure. Lab-grown diamonds meet that definition completely.
When a synthetic diamond is created via the CVD or HPHT process, it grows atom by atom in the same crystalline arrangement as a mined diamond. The result is a stone that is indistinguishable from a mined diamond even under a jewellery loupe — and can only be identified with specialised lab equipment measuring trace elements. A GIA or IGI grading report for a lab-grown diamond evaluates the same four characteristics — carat weight, cut, colour, and clarity — using the same grading standards applied to mined stones.
A true diamond simulant, by contrast, mimics only the appearance of diamond. It has different chemistry, different hardness, different optical properties, and a different refractive index. The practical implications for wearers are significant. A moissanite, for example, will register as "not a diamond" on a standard thermal conductivity tester (though advanced testers can differentiate between diamond and moissanite). Cubic zirconia will scratch, cloud, and eventually require replacement. A lab-grown diamond, treated with the same care as any fine gemstone, will last for generations.
At Riona Jewel, every lab-created diamond in our collection is independently graded and arrives with a GIA or IGI certificate. We personally verify every stone in our collection. The carbon footprint of a Riona Jewel lab-grown diamond is up to 85% lower than its mined equivalent, and every stone is 100% conflict-free by origin. Visit our diamond education center for a comprehensive introduction to the 4Cs and lab-grown diamond grading before you shop.
Shop Riona Jewel Lab-Grown Diamond Rings
From helping over 2,000 couples find their perfect ring, we know that the single most important factor — beyond budget, beyond style — is trust in the stone. Every ring in the Riona Jewel collection is built around a certified, ethically sourced lab-grown diamond centre stone, set in your choice of 925 Sterling Silver, 10K, 14K or 18K gold or platinum. Below is one of our most-loved designs.
14K White Gold 2.0 CT Round Lab Grown Diamond Solitaire Engagement Ring
- 2.0 CT Round brilliant lab-grown diamond centre stone
- IGI certified · VS2 clarity · conflict-free
- 14K White Gold classic solitaire setting
- Free worldwide shipping & lifetime warranty included
- Custom engraving at no extra charge and bespoke sizing.
How to Choose the Right Diamond Alternative: Step-by-Step
Whether you have settled on a lab-grown diamond or are still weighing your options, the buying process follows the same logical sequence. After guiding thousands of couples through this journey, we have distilled it into seven clear steps that eliminate guesswork and protect your investment.
Step 1: Define Your Stone Priority — Real Diamond or Simulant?
The very first question is whether you want a real diamond (lab-grown) or a diamond simulant such as moissanite or CZ. If resale value, long-term durability, and the prestige of owning a certified diamond matter to you, choose a lab-grown diamond. If maximising visible carat weight on a tight budget is the priority and you understand the trade-offs, a high-quality moissanite is an excellent diamond alternative. Be honest about what matters most — both are valid choices when made with full information.
Step 2: Select Your Shape
The cut of your center stone determines approximately 40% of its visual impact. Round brilliant cuts maximize light return and are the most popular globally — accounting for roughly 36% to 45% of total sales in the U.S. and UK. Oval, cushion, and elongated pear cuts create a flattering illusion of size. Emerald and Asscher cuts have a distinctive hall-of-mirrors effect with less fire but extraordinary elegance. Explore our full range of engagement rings sorted by shape to narrow your options before diving into the 4Cs.
Step 3: Set Your Budget and Carat Range
With a lab-created diamond, your budget stretches dramatically further than it would with a mined stone. A 2-carat IGI-certified lab-grown round brilliant that would cost $18,000–$22,000 in a mined equivalent typically starts at $1,288 at Riona Jewel. For moissanite, the same carat weight can be achieved for under $800. Prioritise cut quality above all other Cs — a well-cut 1.5ct stone will outsparkle a poorly cut 2ct stone every time. Our diamond education center has a full breakdown of how to read a grading report.
Step 4: Choose Your Metal
In 2025–2026, yellow gold has experienced its strongest resurgence in over two decades, now representing approximately 40%-57% of new engagement ring metal choices — up from just 15%-22% in 2019. White gold and platinum remain popular for those who want a cool, contemporary backdrop that maximizes a colorless stone's brightness. Rose gold continues to appeal to those seeking warmth and romance.
Step 5: Select Your Setting Style
For diamond simulants and lab-grown diamonds alike, the setting is a critical structural decision as well as an aesthetic one. A four- or six-prong solitaire maximizes light entering the stone and is ideal for brilliant-cut center stones. A bezel setting fully encircles the girdle with metal — protecting the stone from chipping but reducing light intake slightly. A pavé or halo setting uses smaller accent stones to amplify the perceived size of the center stone. For moissanite, we strongly recommend a solitaire or simple pavé setting, as the stone's natural fire is better appreciated without excessive visual competition.
Step 6: Verify Certification and Ask for Documentation
Any reputable seller of a lab-created diamond should provide a GIA or IGI grading report with your purchase. This report is not just a certificate of quality — it is proof of your stone's identity, and it matters for insurance purposes. Moissanite sold by reputable brands will come with their own certification. If a seller cannot provide documentation for any stone they are selling as a diamond or lab diamond, walk away. At Riona Jewel, every certificate is included with purchase and available for download at any time.
Step 7: Confirm Ring Size and Customization Options
Getting the ring size right before purchase saves time and resizing costs. Use our free ring sizing guide — it includes a printable ring gauge, a string method for measuring at home, and conversion charts for US, UK, EU, and Asian sizing standards. If you have a unique vision for your ring, our custom engagement ring design studio can bring it to life from a sketch or reference image.
Mined Diamond vs. Lab-Grown Diamond vs. Moissanite: Full Comparison
Use this table to evaluate every key property side-by-side. Whether you are choosing between a true synthetic diamond and a diamond simulant or simply trying to understand the trade-offs, this comparison is drawn directly from GIA and IGI gemological standards.
| Feature | Mined Diamond | Lab-Grown Diamond (Riona Jewel) | Moissanite |
|---|---|---|---|
| Chemical Composition | Pure Carbon (C) | Pure Carbon (C) | Silicon Carbide (SiC) |
| GIA / IGI Certified | ✓ Yes | ✓ Yes | ◑ Brand cert. only |
| Price (2ct equivalent) | $18,000–$22,000+ | From $1,288 | From $490 |
| Conflict-Free | ◑ Varies by source | ✓ Always | ✓ Always |
| Carbon Footprint | High (mining intensive) | Up to 85% lower | Up to 90% lower |
| Refractive Index | 2.417 | 2.417 | 2.65–2.69 |
| Hardness (Mohs) | 10 | 10 | 9.25 |
| Is It a Diamond? | ✓ Yes | ✓ Yes | ✗ No (simulant) |
| Best For | Heirlooms, collectors | Value, ethics, quality | Maximum size on budget |
As this table illustrates, a lab-created diamond is the only diamond alternative that retains every scientific property of a mined diamond while dramatically reducing both cost and environmental impact. Moissanite is an outstanding diamond simulant for buyers who priorities size and budget over technical equivalence. All Riona Jewel stones are certified, conflict-free, and backed by our lifetime warranty.
Shop by Style: Our Most-Loved Engagement Ring Designs
Whether your style leans toward timeless solitaires, glamorous halos, or romantic three-stone settings, every Riona Jewel engagement ring is set with an IGI-certified lab-grown diamond of VS2 clarity. Browse our most popular styles below — each available in 925 Sterling Silver, 10K, 14K,18K gold or platinum and fully customizable to your vision.
14K White Gold 2.0 CT Oval Lab Grown Diamond Halo Engagement Ring
- 2.0 CT Oval lab-grown diamond with diamond halo surround
- IGI certified · VS2 clarity · conflict-free sourcing
- 14K White Gold — halo amplifies the perceived size of the center stone
- Free worldwide shipping & lifetime warranty
- Available in yellow, white & rose gold and platinum
14K White Gold 2.0 CT Oval Lab Grown Diamond Three-Stone Engagement Ring
- 2.0 CT Oval center flanked by two matching side diamonds
- Symbolizes past, present, and future — a timeless choice
- IGI certified · VS2 · conflict-free
- 14K White Gold, available in multiple metal options
- Free worldwide shipping & lifetime warranty
Before you finalize your choice, we recommend reading our in-depth guides that complement this article:
- How to Buy Diamonds: The 4Cs, Shapes & Smart Shopping Tips 2026 — a comprehensive breakdown of everything you need to understand a grading report and negotiate intelligently.
- How to Measure Ring Size at Home: Ultimate Guide, Charts & Tips 2026 — essential reading before placing any ring order online.
Your Complete Diamond Simulant Buyer's Checklist
Before You Buy — 14-Point Gemologist's Checklist
Frequently Asked Questions About Fab Diamonds & Diamond Simulants
A "fab diamond" is a colloquial term for any fabricated or faux diamond — a stone engineered to resemble a natural diamond. The term can refer to both true diamond simulants (moissanite, CZ, white sapphire) and lab-grown diamonds, though the distinction matters enormously. Lab-grown diamonds are chemically and physically identical to mined diamonds and are considered real diamonds by the FTC, GIA, and IGI. Simulants, by contrast, are different materials that mimic diamond's appearance but do not share its composition, hardness, or optical properties. When shopping, always confirm whether the stone being described as a "fab diamond" is a certified lab-grown diamond or a simulant.
No — lab-grown diamonds are not fake diamonds. They are real diamonds in every measurable scientific sense. The Federal Trade Commission formally updated its guidelines in 2018 to confirm that a diamond does not need to be mined from the earth to qualify as a diamond; it must only be composed of pure carbon in a cubic crystal structure, which lab-grown diamonds are. GIA and IGI — the world's most respected gem grading laboratories — grade lab-grown diamonds using the exact same 4Cs methodology applied to mined stones. Riona Jewel's lab-grown diamonds are GIA- and IGI-certified and arrive with a full grading report confirming their authenticity.
Among true diamond simulants, moissanite is the best choice for an engagement ring intended for daily wear. It scores 9.25 on the Mohs hardness scale — second only to diamond — which means it resists scratching and maintains its polish over decades. Its refractive index (2.65–2.69) is actually higher than diamond's, producing spectacular brilliance and coloured dispersion. Cubic zirconia, while popular and affordable, is significantly softer (8–8.5 Mohs) and will cloud and scratch over time, requiring periodic replacement. However, if you want a stone that is both beautiful and chemically a real diamond, a GIA- or IGI-certified lab-grown diamond remains the strongest recommendation for an engagement ring.
Yes — a trained gemologist with the right tools can distinguish between most diamond simulants and real diamonds, including lab-grown diamonds. Moissanite, for example, is doubly refractive (birefringent), which a gemologist can identify under 10x magnification by the doubling of facet junctions. Cubic zirconia has a higher specific gravity than diamond, weighing noticeably more for a given size — a jeweller can detect this by weighing a loose stone. The key exception is the comparison between a lab-grown diamond and a mined diamond — these are genuinely indistinguishable without specialist laboratory equipment. GIA and IGI reports accompany all Riona Jewel lab-grown diamonds, eliminating any ambiguity about the stone's identity.
Lab-grown diamonds are typically 60–85% less expensive than mined diamonds of equivalent quality. For context, a 2-carat, VS1 clarity, F-colour round brilliant mined diamond might retail for $18,000–$22,000, while an IGI-certified lab-grown diamond of the same specification starts from just $1,288 at Riona Jewel. This dramatic price difference reflects the economics of supply — not any difference in quality, hardness, brilliance, or beauty. The gap has widened in recent years as lab-grown diamond production has scaled globally, making now an exceptional time to purchase. Our collections start from $1,288 for lab-grown diamond engagement rings.
Most diamond simulants — including moissanite and cubic zirconia — do not retain significant resale value, as they are manufactured gemstones with no secondary market comparable to natural diamonds. Lab-grown diamonds occupy a middle ground: while their resale value has declined as production costs have fallen, a GIA- or IGI-certified lab-grown diamond still commands a measurable price on the secondary market. Our honest recommendation is to buy any stone — mined, lab-grown, or simulant — primarily for its beauty and meaning, rather than as a financial investment, as jewellery markets are highly illiquid and resale is rarely straightforward.
Moissanite is technically a diamond simulant — it is a distinct mineral (silicon carbide, SiC) that visually resembles a diamond but is chemically and physically different. It is not a fake diamond in the pejorative sense: it is sold honestly as moissanite, it has its own unique gemological properties, and in some ways — particularly in terms of fire and dispersion — it actually surpasses diamond. Many buyers who understand the difference actively choose moissanite because they love its optical character and its significant price advantage.They are not diamonds, but they are extraordinary gems in their own category.
Among true diamond simulants (excluding lab-grown diamonds, which are real diamonds), moissanite is the hardest at 9.25 on the Mohs scale. This places it significantly above white sapphire (9.0), cubic zirconia (8–8.5), white topaz (8), and glass (5–6). For everyday jewellery — especially rings subject to daily contact with hard surfaces — hardness translates directly to scratch resistance and long-term lustre retention. A moissanite ring worn daily will look essentially the same after ten years with normal care; a CZ ring will likely show visible wear within two to three years.
The care routine for a diamond simulant ring depends primarily on the stone type. Moissanite and lab-grown diamonds can be cleaned with the same methods as natural diamonds — warm water, mild dish soap, and a soft-bristle toothbrush; ultrasonic cleaners are generally safe for both. Cubic zirconia should be cleaned gently with warm soapy water and a soft cloth, avoiding ultrasonic cleaners which can stress the stone over time. For all ring types, remove your ring before swimming, applying hand creams or chemicals, and sleeping.
Yes — custom design is one of Riona Jewel's most popular services, available for lab-grown diamond. Our bespoke process begins with a free consultation where our gemologists discuss your budget, preferred stone, shape, metal, and setting style. We then produce a CAD rendering and wax model for your approval before beginning production. Custom rings typically take three to four weeks from design approval to delivery and are available in 14K or 18K yellow, white, or rose gold, as well as platinum. Visit our custom engagement ring design studio page to begin the process, or book a free one-on-one consultation at rionajewel.com/pages/appointment.
Ready to Find Your Perfect Stone?
Browse our certified lab-grown diamond collections — or start a bespoke design with our gemologists.
