When selecting a diamond, you're choosing between three fundamentally different categories: natural diamonds, lab-grown diamonds, and diamond imitations. Each has distinct characteristics that affect both value and meaning.

Natural diamonds are geological formations created deep within the Earth, each bearing unique characteristics from its natural formation. Lab-grown diamonds are chemically and physically identical to natural diamonds created in controlled laboratory environments, offering a different value proposition in terms of pricing and availability.

Diamond imitations (or "simulants") like moissanite and cubic zirconia are distinct materials with different chemical compositions and physical properties that visually resemble diamonds.

The choice between these three categories comes down to what resonates with you: whether you prioritise natural geological origin, identical diamond properties at a different price point, or the aesthetic of diamond with alternative materials.

Natural Diamonds

Natural diamonds formed between one and three billion years ago under extreme high temperature and pressure approximately 100 miles beneath the Earth's surface.

A natural diamond is composed almost entirely of pure carbon, typically around 99.95 per cent. This chemical composition and internal crystal structure make diamond a unique member of the mineral kingdom.

Rarity is the fundamental value driver for natural diamonds. Large rough crystals are discovered far less frequently than smaller ones, which is why diamond prices increase exponentially with carat weight.

Lab-Grown Diamonds: Laboratory Synthesis

Lab-grown diamonds (or "synthetic") are produced in laboratory settings using advanced technology.

Lab-grown diamonds are produced via chemical synthesis and share virtually all chemical, optical, and physical characteristics of natural diamonds. They are real diamonds.

They are evaluated using the exact same 4Cs (Carat, Colour, Clarity, Cut) as natural diamonds, maintaining consistent quality standards. The 4Cs: Natural and Lab-Grown Diamonds Explained dives into the details.

The two primary methods of lab-grown diamond production include:

• HPHT (High-Pressure High-Temperature): This process replicates the extreme pressure and high temperatures found deep within the Earth, using a metallic flux to facilitate growth.
• CVD (Chemical Vapour Deposition): This method involves heating hydrocarbon gas into plasma, which releases carbon atoms that deposit layer by layer onto a seed plate.

The primary difference for buyers is cost. Lab-grown diamonds typically command lower prices than natural diamonds of equivalent size and quality.

Imitations: Alternative Materials to Diamonds

Diamond imitations are materials used as substitutes for diamonds because they look similar. However, they possess entirely different chemical compositions, crystal structures, and physical properties. Imitations are not diamonds.

Moissanite

Moissanite is a diamond imitation that gained popularity in the late 1990s, particularly for engagement rings, due to its notable brilliance, durability, and intense fire. This material is extremely hard and durable, registering a hardness of 9.25 on the Mohs scale. Though this rating is higher than almost all other gems, moissanite is softer than diamond at Mohs 10.

A distinctive feature of moissanite is its extreme optical dispersion. It has more than twice the fire of diamond. Whilst this provides intense visual effects, in larger sizes (specifically one carat or above) this pronounced fire may make it identifiable as a non-diamond. This extreme display of colour flashes in larger specimens is sometimes referred to as the "disco ball" effect.

The clearest difference between moissanite and diamond is its crystal structure: moissanite is doubly refractive. Diamond, being singly refractive, does not exhibit this characteristic. Due to this doubling effect, when looking through the stone, you may see a double image of its back facets, which can make the interior of the moissanite appear blurred.

Whilst moissanite can be colourless to near colourless, some stones may appear slightly yellow or grey when observed from certain angles.

Moissanite gemstones are not graded by any official gemmological laboratories.

Cubic Zirconia (CZ)

Historically, cubic zirconia has been the most widely used diamond imitation since its introduction in the late 1970s.

CZ is manufactured by placing powdered zirconium oxide inside a metal chamber and heating it to its melting point. CZ is considered a hard and durable material, with a Mohs hardness of 8.5. However, this is significantly softer than diamond.

CZ can be produced in large sizes and in almost any colour. CZ's colourless crystals are generally noted for their high clarity, often having minimal or no visible imperfections. Pink and yellow CZs are used to imitate pink or yellow diamonds, whilst other colours of CZ can serve as substitutes for red, purple, blue, green, or black gemstones.

Optically, CZ displays slightly more fire (rainbow colours) but less brilliance than diamond. A key limitation with CZ is that its colour may fade over time, and CZ will eventually develop a yellowish tinge.

CZ gemstones are not graded by any official gemmological laboratories.

Visuals	Diamond	Moissanite	Cubic Zirconia
Refraction	Bends light once, producing a crisp, clear image inside.	Bends light twice, making lines inside look blurry or doubled.	Bends light once, producing a crisp, clear image inside.
Fire & Brilliance	Unmatched brilliance (white light return). Displays controlled "fire" (rainbow flashes).	Over twice the fire of a diamond; may show excessive rainbow flashes ("disco ball" effect) in large sizes.	Has slightly more fire but less overall brilliance than a diamond.
Durability (Mohs Hardness)	10	9.25	8.5
Wear Signs	Facet edges are very sharp and defined due to extreme hardness.	Facet edges look rounded.	Facet edges look rounded.
Color	Ranges from colorless to light yellow/brown. Fancy colored diamonds exist in other colors.	May look slightly yellow or gray at certain angles.	May yellow over time.
Girdle	Often faceted.	Often smooth and polished	Often faceted.

Others

This category also includes materials like glass, YAG (Yttrium Aluminium Garnet), GGG (Gadolinium Gallium Garnet), spinel, and rutile.

Making Your Selection

Understanding the distinction between natural diamonds, lab-grown diamonds, and imitations allows you to make an informed decision based on what matters most to you. Each category serves different priorities and clarity about these differences ensures your purchase aligns with your values and expectations.

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