F-G SI diamond: what does it mean, and is it good?

Is an F-G SI diamond real?

Yes. F-G SI isn't a type of diamond, and it isn't an imitation. It's a grade: two of the four points every diamond is assessed on. F-G is about colour, SI about clarity. Together they tell you what the diamond looks like, not whether it's real.

What they don't tell you either: where the diamond comes from. At TOV every diamond is natural, across all our gold diamond jewellery.

The 4 Cs in one table

Every diamond is assessed on four points, and they all start with a C: colour, clarity, cut and carat.

Colour: from D to Z

The colour scale runs from D to Z. The further down the alphabet, the more yellow you see.

• D, E and F: colourless.
• G to J: near colourless.
• K, L and M: faint tint.
• N to Z: light yellow to yellow.

F-G sits right on the line: F is the last letter of colourless, G the first of near colourless. Set in gold, you see an icy white stone.

Clarity: where does SI sit?

Almost every natural diamond carries tiny traces of how it grew deep in the earth. They're called inclusions. The clarity scale tells you how many you see at ten times magnification.

SI stands for slightly included. It sits in the middle of the scale: the inclusions are there, but you have to go looking for them.

Why F-G and SI is a smart choice for every day

You don't wear a diamond under a loupe. You wear it on your hand, in your ear or round your neck. What counts is what you see there.

• You see white, not yellow. F-G is bright enough to look icy white next to both white gold and yellow gold.
• You see sparkle, not inclusions. With SI you usually see nothing with the naked eye. In small stones, like those on most jewellery, it shows even less.
• You don't pay for the loupe. Every step up the scale makes a diamond a lot more expensive, for a difference you can't see when you wear it.
• It can take a knock. Diamond is the hardest natural material and very scratch resistant. Exactly what you want in a ring you never take off.

Same ring, three weights: this is what carat does. Choose a diamond engagement ring and you get the same colour and clarity, whichever weight you pick.

From this story

Four Prong Diamond Solitary Ring (0.05 ct) £399.00 Four Prong Diamond Solitary Ring (0.10 ct) £599.00 Four Prong Diamond Solitary Ring (0.15 ct) £759.00

How do you check it?

With the certificate. Every TOV piece comes with a personal digital certificate of authenticity. For diamonds, it states the cut, colour, clarity and carat weight. You'll also find the exact weight on every product page, across all our gold diamond rings.

Buying a diamond somewhere else? Always ask these four questions: which colour, which clarity, how many ct, and natural or lab-grown? A good seller knows straight away. More on the 4 Cs is in our diamond guide.

Natural or lab-grown?

A lab-grown diamond is a real diamond too: the same carbon, the same hardness, the same sparkle. It gets graded on the same 4 Cs, so a lab-grown diamond can be F-G SI as well. Only the origin differs: a natural diamond grew in the earth, a lab-grown one in a lab. We work with natural diamonds. The whole story is in lab-grown vs natural diamond. Rather not have a diamond? Then cubic zirconia set in real gold is a lovely alternative.

Gold Diamond Jewellery Natural diamonds, F-G colour and SI clarity, set in real gold. Shop Gold Diamond Jewellery