4Cs of Diamonds: Diamond Buying Tips | Blue Nile
Find Your Perfect Diamond  | EXPLORE OUR DIAMONDS Find Your Perfect Diamond  | EXPLORE OUR DIAMONDS

Diamond Tips

Use our list of diamond buying tips to navigate the 4Cs. Get advice and discover what to prioritize when making your diamond purchase.

Diamond Cut

  • The sparkle of a well-cut diamond can actually make it appear larger than one might expect based on carat weight alone.
  • Cut is so important to a diamond's overall beauty, Blue Nile gemmologists recommend purchasing the highest cut grade within your budget.
  • All diamonds have varying degrees of brilliance, scintillation, and fire, but a well-cut diamond will always appear beautiful.
  • Poorly cut diamonds will appear dull or glassy, and, in those areas where light leaks out of the bottom of the diamond, may have dark areas.
  • Shape and cut are often used interchangeably, but while shape describes a diamond's form, such as round or oval, cut is a grade that refers to a diamond's light return, or, as we generally think of it, sparkle.
  • Diamonds with the highest cut grades cost more, not only because they are rarer, but also because of the skill and experience needed by the diamond cutter to produce such a beautiful stone. In addition, far more time is required to produce a well-cut stone.

Diamond Colour

  • The human eye tends to detect sparkle (light performance) before colour. This is why colour is generally considered the second-most important characteristic of buying a diamond, after cut.
  • As diamond size increases, colour becomes more noticeable. This is especially important to keep in mind if purchasing a diamond of two carats or greater.
  • The visible difference between diamonds of one colour grade, for example G to H or I to J, is so minor it is difficult to detect with the unaided eye. The cost savings, however, can be significant.
  • Diamond shapes that reflect more light (i.e. have more sparkle), such as round or princess, can mask some colour in a diamond.
  • The type of metal in which a diamond is set can complement its colour. Consider setting diamonds graded I or J in yellow gold. White gold or platinum best complement diamonds with a colour grade of D through H.

Diamond Clarity

  • Most imperfections are so small they cannot be seen by the unaided eye.
  • If your budget is tight, it might be possible to purchase a diamond with a visible imperfection, but hide it beneath a ring claw where it will never be seen.
  • As diamond size increases, the size of the facets also increases. Because facets are essentially windows into a diamond, the importance of purchasing a diamond with a higher clarity grade increases.
  • Asscher- and emerald-shaped diamonds are designed with long facets that emphasise transparency over sparkle. For these diamonds, Blue Nile gemmologists recommend purchasing a diamond with a clarity grade of VS1 or better to ensure the imperfections will not be visible.

Diamond Carat

  • Carat weight alone will not give you an accurate view of a diamond's size, but should be considered in conjunction with the measure in millimeters across the top of a diamond, and the diamond's cut grade.
  • Diamond prices jump at the full-carat and half-carat marks. To get the best value, look for diamonds just below these sizes, for example purchase a .97-carat diamond instead of a one-carat. Visually, you will not be able to see a difference in size, but your savings can be significant.