Find diamond rings and diamond jewellery in a range of carat weights and cuts at Ernest Jones


Diamonds are measured in carats, which take into account the weight, rather than the size. Outsized carat weights are rarer and more precious. Carats are split into points where 100 points are equal to one carat.

  • ½ carat diamond – 50 point or 0.50 carat diamond
  • ¼ carat diamond – 25 point or 0.25 carat diamond

When there is more than one diamond on a piece of jewellery such as on a diamond cluster ring or a three stone pendant, the stones are weighed together rather than individually.

The carat weight does not reflect the size of a diamond. Therefore it may appear bigger but may weigh less, so it is worth taking your time to absorb its splendour.

When buying diamond jewellery, the most appealing factor is likely to be the carat weight of a diamond. However it is important to remember that colour, clarity and cut will also determine the value of a diamond.

Diamond rings with a variety of carat weights


The cut of a diamond refers to their proportion and finish. Skilled craftsmen transform a rough diamond to a gleaming polished diamond by polishing tiny facets into the rough stone. Facets are the flat, polished surfaces on a diamond. Well cut and proportioned facets on a diamond will make good use of light, allowing it to be dispersed and reflected from one facet to another, releasing the diamond’s brilliance.

A diamond can be cut in various ways; to be heavier, thus gaining more value, or to hide or minimalise inclusions. Symmetry, proportion and how polished a diamond is will all determine the quality of the cut. These can vary from diamond to diamond, so the shape and the quality should be taken into consideration.

There are three main cutting styles each has its own facet arrangements:

  • Brilliant cut
  • Step cut
  • Mixed cut
  • Diamond shapes
A diagram showing the many facets of a cut diamond including the table, the crown and the cullet