The Complete Diamond Buying Guide

Before diving into quality factors, it helps to understand the two main categories of real diamonds available today: mined (natural) diamonds and lab-grown diamonds. Both are genuine diamonds with identical chemical, optical, and physical properties. The difference lies entirely in how and where they are formed.

Natural (Mined) Diamonds

Natural diamonds formed deep within the Earth’s mantle, approximately 150-200 kilometres below the surface, under extreme pressures and temperatures over periods spanning one to three billion years. They were brought to the surface by volcanic eruptions and are extracted through mining operations. Natural diamonds have been treasured for centuries and carry the romance of geological time. However, they come with a significant price premium and carry environmental and ethical considerations related to mining.

Lab-Grown Diamonds

Lab-grown diamonds are produced in controlled laboratory environments using technology that replicates the conditions under which natural diamonds form. The two production methods are HPHT (High Pressure, High Temperature) and CVD (Chemical Vapor Deposition). The resulting diamonds are atom-for-atom identical to mined stones. They are graded by the same independent laboratories using the same criteria and are visually indistinguishable even to trained gemologists without specialised equipment.

The key advantages of lab-grown diamonds are cost (50-70% less than equivalent mined diamonds), guaranteed conflict-free origin, full traceability, and a significantly lower environmental footprint. For a detailed side-by-side analysis, read our Lab-Grown vs. Natural Diamonds Comparison.

Diamond Simulants (Not Real Diamonds)

It is important to distinguish lab-grown diamonds from diamond simulants like cubic zirconia (CZ) and moissanite. Simulants may look similar at a glance but have entirely different chemical compositions and physical properties. CZ is made of zirconium dioxide, while moissanite is silicon carbide. Neither has the same hardness, brilliance characteristics, or long-term durability as a real diamond. Lab-grown diamonds, by contrast, are real diamonds in every measurable way.

The 4Cs -- Cut, Colour, Clarity, and Carat Weight -- are the universal framework for evaluating diamond quality. Understanding how they interact is the single most valuable piece of knowledge you can bring to the diamond-buying process. Here is a concise overview of each, with our recommendations for maximising beauty within any budget.

The 4Cs are deeply interrelated. A poorly cut 2-carat diamond will look less impressive than a beautifully cut 1.5-carat stone. Similarly, paying for VS1 clarity in a shape that naturally hides inclusions (like a round brilliant) is money that could be better allocated to carat weight. For a deep dive into each factor, including grade tables and expert strategies, visit our full 4Cs Diamond Guide.

Diamond shape refers to the outline of the stone when viewed from above. It is distinct from “cut,” which refers to how well the facets interact with light. Shape is a deeply personal choice that reflects individual style, and each shape has unique optical characteristics that affect how the diamond appears on the hand.

The round brilliant is the most technically optimised shape, with 57-58 facets mathematically arranged for maximum light performance. It accounts for the majority of diamond sales worldwide. However, fancy shapes are gaining popularity rapidly, particularly ovals, which offer a larger face-up appearance per carat weight and an elongating effect on the finger.

When selecting a shape, consider not only personal style but also practical factors. Emerald and Asscher cuts have large, open facets that reveal inclusions more easily, so higher clarity (VS2 or above) is recommended. Round brilliants and cushion cuts are more forgiving of inclusions because their facet patterns scatter light more effectively. Pear and marquise shapes should be checked for the “bow-tie effect,” a dark shadow that can appear across the centre of poorly cut elongated diamonds.

A diamond certificate -- also called a grading report -- is an independent assessment of a diamond’s quality by a gemological laboratory. It is arguably the most important document in any diamond purchase, serving as an objective, third-party verification of the 4Cs and other characteristics. Without certification, you are essentially taking the seller’s word for the diamond’s quality, which is a significant risk given that subtle differences in grade can mean hundreds or thousands of dollars in value.

The two most respected diamond grading laboratories are IGI (International Gemological Institute) and GIA (Gemological Institute of America). For lab-grown diamonds specifically, IGI is the industry standard and has certified more lab-grown stones than any other laboratory worldwide. Every diamond at Aurela Diamonds comes with full IGI certification, which you can verify online at any time.

Certification is also essential for practical reasons: insurance companies require it for coverage, it simplifies the resale or upgrade process, and the unique certificate number laser-inscribed on the diamond’s girdle provides a permanent form of identification. Think of it as an investment in trust and transparency.

Getting the most beautiful diamond for your money is not about finding the cheapest option -- it is about understanding where to invest and where to save without sacrificing visual beauty. Here are the strategies professional buyers use to maximise value.

Another often-overlooked tip: consider the shape of the diamond. Fancy shapes (everything other than round) are typically 20-40% less expensive per carat than round brilliants because round diamonds lose the most rough material during cutting. An oval or cushion diamond can deliver more size and beauty per dollar than a round of the same carat weight.

The landscape of diamond retail has changed dramatically. Gone are the days when a high-street chain jeweller was your only option. Today, you can buy from online-only retailers, brick-and-mortar jewellers, independent designers, and hybrid businesses that combine both approaches. Each has advantages and trade-offs.

Large online retailers offer extensive inventories and competitive pricing but often lack personal service. Traditional brick-and-mortar stores provide a hands-on experience but may have limited selection and higher markups to cover retail overhead. The sweet spot, in our opinion, is a business that offers both: an online presence with transparent information and pricing, combined with personal consultation -- either in person or virtually -- from a knowledgeable team.

Regardless of where you buy, insist on the following: independent certification from IGI or GIA; high-resolution imagery or video of the specific stone you are purchasing (not generic stock photos); a clear return or exchange policy; and responsive, knowledgeable customer service that can answer your questions without pressure. At Aurela Diamonds, we believe in complete transparency. Every diamond in our collection is IGI certified, and our team is available for personalised consultations to ensure you find exactly the right stone for your needs and budget.

Even well-informed buyers can fall into common traps. Awareness of these mistakes will save you money and help you choose a more beautiful diamond. Here are the most frequent errors we see.

1. Overpaying for Colour and Clarity

This is the single most common mistake. Paying for D colour or Flawless clarity is spending money on differences that are invisible to the naked eye. A G-colour, VS2 diamond looks identical to a D-colour, IF diamond when set in a ring and viewed at arm’s length. The price difference can be 40-60%. Invest those savings in cut quality or carat weight instead.

2. Neglecting Cut Quality

Some buyers focus entirely on carat weight and sacrifice cut to get a bigger diamond. This is backwards. A beautifully cut 1-carat diamond will genuinely outperform and outshine a poorly cut 1.3-carat diamond. Cut is what makes a diamond come alive with light. Always prioritise cut grade -- it is the difference between a diamond that takes your breath away and one that looks dull.

3. Buying Without Certification

An uncertified diamond is a gamble. Without an independent grading report from IGI or GIA, you have no objective verification of the diamond’s quality. Sellers can (and do) exaggerate grades on uncertified stones. Always insist on proper certification.

4. Fixating on Carat Weight Thresholds

Diamond prices jump significantly at “magic” sizes: 0.5ct, 0.75ct, 1.0ct, 1.5ct, and 2.0ct. A 0.98ct diamond costs meaningfully less than a 1.01ct diamond but is visually indistinguishable. Buy just below these thresholds for better value.

5. Ignoring the Setting

The setting is not an afterthought. A well-chosen setting enhances the diamond’s appearance, protects it, and completes the ring’s aesthetic. Consider how the setting’s metal colour affects the diamond’s perceived colour, and how the prong style affects the amount of light entering the stone.