Garnet vs Ruby: Key Differences and Distinguishing Features

For almost as long as Homo sapiens have existed, we’ve used precious stones as symbols of status. If you aren’t familiar with gemstones, you may question if garnet and ruby, both rich red jewels, are truly different. In fact, all red gemstones used to be called ‘rubies’, but we now understand the difference in hardness, geological formation (which affects colour variants), rarity, and clarity between ruby and garnet.

The ruby, considered one of the “Big Four” gemstones, is scientifically labelled corundum. (Corundum also formulates as other colours, which are then labelled sapphires.) Corundum is made up of aluminium and oxygen atoms.

Garnets are actually a group of silicates, minerals containing silicon and oxygen. There are over 20 garnet categories, called species. Only around five are important in the gem industry: pyrope, spessartine, andradite, almandite, and grossularite.

In short, there are only red ruby gemstones, whereas garnet gemstones have multiple colour variations. Rubies, also called the “king of gems”, get their red from chromium trace elements. These intensely coloured gemstones absorb green and yellow, giving them a more saturated blood-red shade. They have a cooler undertone than garnets, showing hints of purple and blue.

Red garnets are the most iconic among the garnet family, but this gemstone also presents in yellow, yellow-green, orange, pink, purple, blue, and black. The red ones get their colour from the presence of iron during their volcanic forming process. If you compare a garnet and ruby side by side, the former appears less fiery red than the latter.

Garnets are much more abundant than rubies, and naturally so, given that multiple silicate minerals fall under the name. Red garnets are relatively common while green and peach garnets are harder to find.

Rubies larger than one carat and without many inclusions are extremely rare. While there are plentiful amounts of conundrum underground, very few of these recovered gemstones are gem-quality. In fact, high-quality rubies are more scarce than white diamonds. However, created ruby roughs of various sizes can be produced on-demand in a controlled laboratory setting.

Red garnets generally do not have eye-visible inclusions. Rubies, on the other hand, can contain nine types of inclusions, four of which are fairly distinctive in rubies:

• Silk: Fine threads of another mineral, called rutile, that look like silk fibres
• Scratches: Thin white surface scrapes
• Fingerprints: Cloudy inclusions resembling fingerprints that form when corundum recrystallizes to heal a fracture
• Colour zoning: Inclusions that make the gemstone’s colour appear uneven

In contrast, lab-grown rubies contain few to no inclusions. While the lab process closely imitates the natural ruby formation process, it is controlled to a point that few imperfections occur. These created gemstones appear very clean to the naked eye.

Ruby has a hardness of 9 out of 10 on the Mohs scale, ranking it the second-hardest gemstone after diamond. This durability makes ruby gemstones ideal for long-lasting jewellery such as engagement rings. Garnet is slightly softer at 6.5 to 7.5 on the Mohs scale, making this coloured gemstone more susceptible to chipping or scratching.

Due to its relative rarity, the July birthstone of ruby can fetch a much higher price than garnet. Gem-quality rubies are among the most expensive gemstones on the market, with their unmatched saturation of red and (nearly unmatched) hardness. High-quality ruby prices can range anywhere from a few hundred USD to over $100,000USD per carat, while garnet ranges from $150USD to maximum $7000USD per carat.

When you hold a garnet against a bright light source, it’ll show a band of rainbow colours, whereas if you do the same to a ruby, it will not show the entire rainbow spectrum because it absorbs the green and yellow light.

As previously mentioned, rubies often contain more inclusions than garnets. Red garnets have few eye-visible inclusions, appearing more watery-clear.

Rubies are pleochroic. Some garnets exhibit colour change, best known in alexandrite, where they appear blue under natural light and red-purple under artificial light.

To sum up the key differences between precious stones ruby and garnet, ruby is harder, conveys a deeper red hue, and is generally more expensive than garnet. Rubies are prized as one of the most desired gemstones in the world for these qualities. Garnet is a valued jewel in its own right, with a wide range of colour varieties, greater clarity, and availability, making it a beautiful gemstone that’s also a sustainable choice. With BIRON® lab-created rubies, you can have all the distinct fire of natural rubies at a lower price without the detrimental effects of mining.