Diamonds and sapphires can look very similar to the untrained eye although they're incredibly different gemstones. Both stones are very valuable and a popular choice for jewellery, including wedding rings, engagement rings and solitaire pendants. They’re also both used to symbolise love, faith, commitment and trust. So, how can you tell the difference between these precious stones when you’re buying or selling diamonds and sapphires? Here’s a look at the differences between these two gemstones in terms of structure, formation and price.
While this difference won’t be noticeable to the naked eye, diamonds and sapphires have very different structures. A diamond is made of pure carbon that crystallizes into cubes. This compact structure makes diamonds the hardest gemstone on earth with a hardness of 10 on the Moh’s scale. Pure carbon diamonds are absolutely colourless, although their structure can contain small amounts of other elements that produce yellow, brown, blue, pink, red and green diamonds. Sapphires, on the other hand, have a hexagonal shape composed of aluminium oxide crystals. Sapphires are the second hardest gemstone on earth with a hardness of 9 on the Moh’s scale. Sapphires also come in many colours when other elements make their way into the crystal during formation.
Differences in Formation
These prized gemstones also form in completely different ways. Sapphires form naturally in a hexagonal shape in rocks like granite, gneiss and schist due to changes in heat and pressure. They can be found in igneous (cooled magma) and metamorphic (transformed) rocks. The colour of the sapphire comes from the presence of other minerals. Iron produces yellow or green sapphires, vanadium produces purple sapphires and titanium creates blue sapphires. Sapphire gems can also be red, although they're called rubies, not sapphires.
Diamonds, on the other hand, require very precise conditions to form deep in the earth with extreme pressure and relatively low temperature. There are two places on earth where diamonds can form: deep in the earth’s lithospheric mantle and at spots where a meteorite has struck the earth. These gemstones slowly make their way to the surface through volcanic pipes and diamonds that are mined today are anywhere from 1 billion to over 3 billion years old.
The price of these gemstones is determined by their carat weight, cut, clarity and colour, whether you’re buying or and sapphires. In general, sapphires tend to be much more affordable than diamonds because they’re easier to mine and more abundant on the earth’s surface.
Both gemstones make beautiful jewellery. Choosing between the two depends on your preference and budget. If you plan to buy and sell diamonds, however, it’s important to make sure you’re not getting colourless sapphires which aren’t usually worth as much.
by Mark Cowden