Princess, Asscher, radiant and square cushion compared on price, sparkle, durability and the clarity grade each one really needs.

A 1 carat pear is about 8.5 x 5.5mm. Size by ratio, how it compares to a round, and the bow-tie effect no certificate shows.

Carat-to-mm size chart for emerald cut diamonds, what 1, 2 and 3 carats look like on the hand, and how to pick the right size.

A halo is a circle of small diamonds around the centre stone. What it does to size, price and everyday wear, explained plainly.

Cushion cuts cost less than rounds, but not as much less as you think once the ring is made. Honest UK price guidance.

Brilliant cut is a faceting style, not a quality grade. Here is when it costs more, when it does not, and what you actually get.

Rose cuts usually cost less per carat and look bigger for their weight, but there are three situations where they cost more.

The round brilliant is the priciest diamond shape per carat. Here is why, how every other shape compares, and which gives the most size.

Baguettes cost less per carat than round diamonds, but finished rings often cost the same. We use our own prices to explain why.

When were diamond engagement rings invented, how long have diamonds been used, and how they became the default choice. A clear UK guide.