Last updated on May 15, 2023
Spinel and ruby are among the most stunning and sought-after gemstones. These gems have similarities; however, they also have distinct differences that make each stand out. In this article, we will provide a comprehensive comparison between spinel vs ruby and explore the various factors that make these gemstones so desirable.
Spinel vs Ruby Formation
Spinel and ruby are both formed under vastly different geological conditions.
Spinel is a magnesium aluminum oxide mineral that forms in metamorphic and igneous rocks. It commonly occurs in limestones that have undergone metamorphism and in ultramafic rocks such as peridotite. Spinel can also be found in volcanic rocks like basalts and skarn deposits. It is often formed in association with other minerals like garnet, pyroxene, and olivine.
On the other hand, ruby is a variety of the mineral corundum, which is an aluminum oxide mineral. Ruby forms in metamorphic and igneous rocks, particularly in marble, gneiss, and basalt. It is usually found in association with other minerals such as kyanite, garnet, and zoisite. The colour of ruby is attributed to the presence of chromium and iron impurities during its formation.
The conditions required for the formation of spinel and ruby are pretty distinct, and the minerals are often found in different types of rocks. While spinel is more commonly found in metamorphic and ultramafic rocks, ruby is predominantly found in metamorphic and basaltic rocks. However, both minerals can occur together in certain geological settings. For instance, spinel and ruby are sometimes found in the same marble deposit in Myanmar.
Spinel vs Ruby Colour
One of the most notable differences between spinel and ruby is their colour.
Ruby is known for its intense red colour, caused by the presence of chromium and iron impurities in the mineral. The colour of ruby can range from pinkish-red to deep blood-red. The more intense and saturated the red colour, the higher the value of the ruby.
On the other hand, spinel comes in a wide range of colours, including red, pink, blue, purple, orange, and black. However, the most prized spinel colours are red and pink, rivalling the best rubies. In fact, spinel was often mistaken for ruby in ancient times due to their similar colour caused by the presence of chromium and occurrence in the same locations.
Ruby is typically a deeper, richer red colour than spinel. It often has a slight bluish undertone, which gives it a cool, elegant appearance. In contrast, spinel can range from a bright, almost pinkish-red colour to a darker, more maroon shade. Another difference between the colour of spinel vs ruby is the way they reflect light. Ruby has a strong red fluorescence, which gives it a beautiful glow under certain lighting conditions. Spinel, on the other hand, has a softer, more subtle red glow.
Ruby’s colour is more limited, but its intense red is highly sought after and commands high prices. Spinel’s variety of colours makes it a versatile gemstone that can be used in a range of jewellery designs, and its red and pink shades offer a more affordable alternative to ruby.
Spinel vs Ruby Clarity
Spinels occur in transparent, translucent, and opaque varieties, and they are typically highly transparent, which makes it easy to spot any blemishes or inclusions within the gemstone. Generally, the clearer the spinel, the more valuable it is considered. However, some spinels may feature unique and charming fingerprint-like inclusions that add to the stone’s character.
Rubies, on the other hand, typically display inclusions, which are not viewed as negative attributes. In fact, these flaws are often seen as an integral part of the character of rubies, and the absence of inclusions is a potential indicator of synthetic stones. Synthetic rubies tend to be eye-clean, while natural rubies almost always display some form of inclusion.
Spinel vs Ruby Durability
When comparing the durability of spinel vs ruby, both gemstones are considered to be quite durable, but ruby is slightly harder than spinel.
Ruby is a very hard and durable mineral, with a rating of 9 on the Mohs hardness scale. This makes it one of the hardest gemstones available and makes it ideal for use in jewellery that is worn regularly. Ruby’s hardness also means it is relatively resistant to scratches and chips.
Spinel, on the other hand, has a hardness rating of 8 on the Mohs scale, which is slightly lower than ruby. While spinel is still a durable gemstone, it may be more susceptible to scratches and chips over time, particularly if exposed to harsh chemicals or other abrasive materials.
Despite these differences in hardness, both spinel and ruby are considered to be durable enough for everyday wear, and they can both be used in a variety of jewellery designs. However, if you are looking for a gemstone that is particularly resistant to wear and tear, ruby may be a slightly better choice due to its higher hardness rating.
Spinel vs Ruby Availability and Price
When it comes to availability and price, there are some notable differences between spinel and ruby.
Ruby is considered to be one of the rarest gemstones in the world, and high-quality rubies are incredibly valuable. The most valuable rubies are those that are a deep, rich red colour with excellent clarity and very few inclusions. Rubies of this quality are becoming increasingly difficult to find, and as a result, their prices continue to rise.
On the other hand, spinel is a more abundant gemstone. While some spinels can be quite valuable, they are generally more affordable than rubies of comparable quality.
In recent years, spinel has become more popular in the gemstone market, which has led to an increase in demand and prices for certain types of spinel. However, in general, spinel is still considered to be a more affordable alternative to ruby, making it an excellent option for those who want a beautiful gemstone without breaking the bank.
Spinel vs Ruby Properties
|Chemical Name||Magnesium aluminum oxide||Aluminium oxide|
|Colours||Red, yellow, orange, brown, blue, violet, purple, pink, green, black, grey and colourless||Red|
|Hardness||8 on the Mohs scale||9 on the Mohs scale|
|Refractive Index||1.71 - 1.73||1.76 - 1.78|
|Specific Gravity||3.54 ~ 3.63||4.0 - 4.1|
|Transparency||Transparent to opaque||Transparent to opaque|
|Fluorescence||Red spinel - subtle red, blue spinel - weak reddish and green||Strong - carmine red|
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