Black diamonds vs black sapphire vs spinel

Black Diamonds, Sapphires and Spinels - Comparing Black Gemstones

Black gemstones, there are so many different options! Which one do you choose? Let's break it down to give you all the information you need before creating your custom piece. My personal favourites and top 3 choices are black diamonds, black sapphires and black spinels.

If you're looking to create a black gemstone piece, do send me an inquiry at and I will be happy to send you a selection of gemstones to choose from.


Aesthetic Differences

Right away you are going to notice that the black diamond has almost a metallic finish while black sapphires and spinels are more jet black. Black diamonds complement men's jewelry very nicely, because that metallic shine tends to look a bit more masculine. 

black diamond, black spinel, black sapphire visual comparaison

Here is an example of a men's bracelet that used black diamonds! Black gemstones pair very nicely with yellow gold. This piece also showcases how well black diamonds can pair with other gemstones, such as rubies.

honeycomb gold mens bracelet black diamondsgold bracelet black diamonds ruby
Black sapphires and spinels tend to be a bit more neutral, which favours women's jewelry, although you can do whatever you think looks best. Below is an engagement ring with a black sapphire.
black sapphire emerald cut engagement ring with diamonds gold

Price Point

 They are all affordable stones. On average you will spend 1000$ to 2500$ per carat for black diamond, 200$ to 400$ per carat of black sapphire and black spinel for 50$ to 150$ per carat. Comparatively to other stones, they also don't grow exponentially in price as the carat increases. Which means you can still find nice sizes without breaking the bank.

Importance of cut

I would recommend investing in a better quality stone and a good quality cut. Because of the affordable price of the raw material, you are almost paying more for labour. This is important because the cut is what will make it sparkle. With black gemstones, no light is passing though. The only time you get sparkle, is when light hits the surface directly, therefore the facets need to be well cut or your stone will appear dull.

Refractive Index 

Obviously diamonds are going to be the shiniest with a refractive index of 2.4. Below that black sapphire and black spinel basically the same, sitting in the 1.7 to 1.75 range. They have a really nice lustre when compared to other alternatives which is why they are some of my favourites. 


All 3 have a good hardness: black diamonds are 10/10, black sapphires are 9/10 and black spinel is 8/10. Especially for something like an engagement ring, you want to have a harder stone so it can resist everyday wear. But also, harder stones will wear down slower, meaning your facets will last a lot longer. If your stone is too soft, your facets will wear down and you will lose brilliance.


Let's explore some other options that did not make it into the top three. Black tourmaline is often found in large crystals, it is a 7/10 for hardness, but usually has a lot of fractures which is why I don't recommend it. Black obsidian, is a 5.5/10 and is a little bit soft. Black onyx is very common, but is also just a 6.5/10. These are very inexpensive options, but if you are looking for something on the more affordable side, I would recommend choosing a black spinel over these.

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