More Than Meets the Eye: Why carat weight isn’t everything when ring shopping

More Than Meets the Eye: Why carat weight isn’t everything when ring shopping

Seeing this, you probably already know a thing or two about jewellery. You can probably even picture a one-carat diamond in your mind's eye, a dazzling round brilliant, a graceful pear shape, or a classic oval. Now, maybe you’re pretty good at that, but hold that image. Now, imagine a one-carat sapphire. It's not going to look the same. What about a one carat emerald? It won't be the same size either.

So, why the difference? It all comes down to a fundamental property of gemstones: specific gravity.

In the world of fine jewellery and precious gems, a carat is a unit of weight, not size. One carat is equivalent to 0.2 grams, which means one gram is five carats. This is a standard measure for all natural gemstones. 

However, just as one gram of feathers looks very different to one gram of lead, there is a big difference in the relative density of gemstones, which directly impacts their size at a given carat weight.

Emeralds and rubies are a great example of this. Despite their shared status as highly sought-after gemstones, they are actually very different in terms of density and weight. A one-carat emerald will appear larger than a one-carat ruby because emeralds have a lower specific gravity. This is a crucial detail for anyone shopping for unique engagement rings or bespoke jewellery - especially online! 

Of course, there is always the issue of cut. A stone with a shallow cut can be a "spready" stone, as we call it in the jewellery trade. This means it looks visually larger from the face-up view than you would expect for a stone of its weight. This is a key factor when considering a stones visual impact. A well-cut stone can maximise brilliance and fire, but a less-than-ideal cut can make a stone appear larger or smaller than its weight suggests.

Long story short, if you only ever see carat weight referenced for a piece of diamond jewellery or gemstone jewellery, don't be afraid to ask for the measurements in millimetres as well. This extra information will give you a much more accurate idea of the stone's actual size and help you make a more informed purchase, whether you're looking for a diamond engagement ring or a stunning piece of heirloom jewellery.