4C'S Of Diamond

The four Cs of diamonds' cut, colour, clarity, and carat determine a diamond’s quality and value. Cut affects brilliance, and an excellent cut can reflect nearly 90% of light. Around 70% of diamonds are sold near-colourless on the D to Z scale. About 80% of diamonds have inclusions not visible to the naked eye. Diamonds over two carats are rare making up only 1-2% of mined stones.

Cut

  • Cut directly determines how effectively a diamond reflects and refracts light, making it the most important factor in overall brilliance.
  • Well-cut diamonds can return up to 90-95% of incoming light, resulting in exceptional sparkle and fire.
  • Poor cut proportions cause light leakage through the sides or bottom, making the diamond appear dull even with higher carat weights.
  • Precision in symmetry, polish, and angles plays a major role in achieving higher cut grades such as Excellent or Ideal.

Colour

  • Diamond colour is graded from D (completely colourless) to Z (visible yellow or brown tones) under controlled lighting.
  • Differences of one or two colour grades are often imperceptible to the naked eye, especially once the diamond is set.
  • White metals like platinum and white gold highlight colourlessness, while yellow or rose gold can mask warmer tones.
  • Near-colourless diamonds (G-I) offer strong visual appeal while providing better value than higher colour grades.

Clarity

  • More than 80% of natural diamonds contain inclusions formed during their creation under extreme pressure.
  • Clarity is graded under 10x magnification, meaning many inclusions are invisible in everyday wear.
  • The position, size, and type of inclusions determine whether they affect brilliance or durability.
  • Eye-clean diamonds balance beauty and value, avoiding the premium cost of flawless grades.

Carat weight

  • Carat measures weight, not size, with 1 carat equal to 200 milligrams.
  • A well-cut diamond can appear 10-15% larger than a poorly cut diamond of the same carat weight due to better light return and face-up spread.
  • Visual size also varies by diamond shape, with elongated cuts often appearing larger on the finger.
  • Pricing increases at popular carat milestones (such as 0.50ct, 1.00ct, and 2.00ct). Choosing a diamond just below these thresholds (e.g., 0.90-0.95 ct) can save 10-25% with little to no visible difference in size.

Certification & Origin

  • Diamonds certified by reputable labs (e.g. GIA, IGI, AGS) provide verified grading and assurance of authenticity.
  • Origin of the diamond can impact ethical considerations and resale value.
  • Certified diamonds are easier to insure and enhance long-term investment confidence.
  • Documentation includes detailed information on cut, clarity, colour, carat, and additional quality factors.

Fluorescence & symmetry

  • Fluorescence is the glow diamonds exhibit under UV light, which can affect appearance and value.
  • Symmetry refers to the alignment of facets, which influences how light travels through the diamond.
  • Diamonds with strong symmetry and optimal fluorescence appear more brilliant and balanced.
  • Both factors are considered during certification and can impact resale value and visual appeal.

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At Robert Cliff Master Jewellers, we blend craftsmanship with personal expression — from classic solitaires to bespoke wedding sets you won’t find anywhere else. Every ring tells a story — let us help you design yours.

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