Marilyn Monroe was on to something when she sang "Diamonds are a girl’s best friend".

If you’re planning to pop the question, you’re probably hopeful that your beloved loves you more than a drop of fossilised carbon, but you never know. So to guarantee a "yes" when you bend down on one knee, it pays to buy the best ring you can afford, just in case.  

Traditionally, an engagement ring will cost about a month’s wages. So you want to choose well. Before you head to the jeweller for their expert advice, here is our handy guide to choosing diamonds, to help you sort the bling from the real thing.

Choosing a diamond essentially comes down to the four C’s – cut, colour, clarity and carat.

Diamond Cut

A diamond’s cut is its most important feature. The better a diamond is cut, the better the quality.

A high quality diamond should reflect light at the top, if it’s cut too shallow or too deep, the light reflects in other directions.

If you want those brownie points with your spouse, make sure you can see light at the top!

Diamond Colour

Did you know the best quality diamonds are colourless?

Colour grading is the most important feature of the diamond, after its cut. Diamonds colours are ranked from D through Z. D is the best colour grade – colourless, while Z has a yellow tint.

Most jewellers like to work with diamonds that are graded J or higher, so don’t worry too much about getting a yellow diamond.

Diamond Clarity

A diamond’s clarity measures the number and size of imperfections in the diamond. All diamonds contain some imperfections as a result of the diamond’s development deep in the earth. Don’t stress too much – most imperfections are so small only a professional jeweller will spot them, so you’re covered (unless your spouse is a jeweller!).

Diamond Carat

The weight of a diamond is measured in carats, but this doesn’t necessarily correspond to its size.

Take carat weight into consideration last, as it doesn’t affect the quality of the diamond.

To give you reference, the more popular sizes are 1/2 carat, 1 carat and 2 carat.

The best thing to do when deciding how many carats should be in the diamond, factor in the size of the ring finger. Usually, the smaller the finger, the smaller the stone (but each to their own!)

Now you’re ready to tackle a visit to the jeweller and ask the right questions about what you hope will soon be your beloved’s best friend.