Dealer's Guide to Buying a Diamond: Spread

My life has been non-stop recently; balancing moving to the big city, fully qualifying as a gemmologist, starting a new job and, of course, running SHJB! However, I have finally settled into some form of routine and now I am super excited to just get back to my blog and chat gems with all of you!

In honour of my new job working as a diamond dealer/ grader in Hatton Garden I thought I would do a series of blog posts on something that I get asked A LOT: how do I buy a good diamond for my money?

The first one I am going to touch on is probably, in most people’s eyes, the most important: the size of your stone! The weight of a diamond is measured in carats and this is a good way to estimate how big you want your stone to look.

However, what often isn’t explained to clients is that the carat weight of the stone is not down to its proportions but its average mass. As a result you can get a 1ct diamond that looks ‘big’ and a 1ct diamond that looks ‘small’; if your stone is cut with a wide table and a shallow pavilion (have a look at the picture below) it may well have the same carat weight as another stone, but it will look significantly wider when it has been set; we call this the ‘spread’ of the diamond. The two diamonds in the picture opposite are 0.3ct apart, and the larger diamond by carat is actually the one that looks smaller! So if you want more flash for your cash, have a look into getting a stone with a big spread, it will look like you’re supporting a much bigger stone whilst actually weighing less, and therefore costing less! What is not to love with that!

A second tip to do with the size of the diamond you opt for gets a tad more technical. Diamonds are a serious commodity and, as such, are subject to standardised prices in the trade. These diamond price lists are published weekly by Rappaport and are massive spreadsheets, which tell you the maximum price you can sell a diamond for based on their carat weight, clarity and colour.

So if you want to know the price of your diamond you go to the Rap List (as it is known in the trade), you find the carat weight section that relates to your diamond i.e. 1.50ct- 1.99ct. You then look down the left axis to find the colour of your stone, and then, finally, work across the top axis to find your diamond’s clarity; where your finger lands: bingo, that’s the maximum price, currently, for your stone in dollars!

If you managed to follow that ove

r-complicated description then stick with me because here’s the trick. As the Rap list is divided into certain carat weights (like 1.50ct-1.99ct) a 1.50ct D VS1 actually has the same standardised price as a 1.99ct D VS1! And t

hat is the clincher! If you find a diamond that sits right at the top of one of the Rap brackets in terms of size then you, technically, will be getting a better deal as you would, most likely, be paying something very similar for quite a significantly smaller stone!

And on that bombshell…

Next week I will be undoing the bad reputation we have given diamonds with fluorescence.