Are Rubies Expensive?

How much are rubies worth? The best rubies are some of the most expensive colored gemstones on the market. One example is the 55.22 ct. Estrela de FURA which sold in 2023 for more than $600,000 per carat. However, you can find rubies at many different price points. 

The IGS Gem Price Guide estimates that the average retail price for a ruby ranges from over $600 per carat to almost $16,000 per carat. To narrow that price range and find a gem that fits within your budget, you should understand the factors that dictate the final value of a stone. The most important factors that determine ruby value are color, origin, treatment, clarity and size.

The Most Important Value Factor for Ruby is Color

By far, the most important value factor for rubies is their color. People have valued rubies for their deep red color for a very long time. Yet, despite this wide recognition, many don't realize that rubies are not actually a gemstone species. Rather, they are a color call for corundum, the same species that includes all colors of sapphire. For a sapphire to earn the moniker "ruby", its color must exhibit a dominant red hue. 

Gemologists evaluate color based on three factors: hue, tone, and saturation. There are four possible hues that qualify corundum as ruby: red, strongly purplish red, slightly purplish red, and orangey red. 

The most valuable hues are pure red and red with a minor contribution of purple. Stones that have more noticeable purple or any orange are automatically assigned a lower per-carat value. 

Of the three aspects of color, tone is arguably the most important factor when it comes to rubies. This is because tone separates red rubies from the more affordable pink sapphire. Unfortunately, as for where exactly the line is between the darker ruby and lighter pink sapphire, the answer differs depending on where you are and who you are speaking with. Professional laboratories like the GIA have masterstones that they use to standardize their color grading in-house, but there is no accepted universal standard such as has been implemented for diamonds.

If this strikes you as odd, it probably should. There is such a monumental difference between the per-carat values of ruby and pink sapphire, one would think that this problem would have been solved long ago. Alas, it hasn't. An exact borderline for what tone is too light for the color to be considered red does not exist. From the perspective of sellers, they will likely want as much of their inventory as possible to be listed as ruby to make more money. Alternatively, buyers would rather gems be listed as pink sapphire so they will pay less. 

Now, while this is a serious issue, it is important to note that it only affects a small number of rubies that are right on the cusp of being too light to be red. The tone of most stones is clearly either one or the other. When it comes to those few gems that might go either way, obtaining a grading report from a reputable lab before you make a purchase is essential. While the individual labs may not agree all the time, having a legitimate report will give you peace of mind. 

While tone dictates whether or not a corundum gem can be called a ruby in the first place, the saturation also has a huge impact on price. This is very straightforward - the stronger the saturation, the greater the value. Collectors seek out rubies with a bright, vivid coloration.

Considering these three aspects of color, the combination that commands the highest per-carat values are red or slightly purplish red with medium to medium-dark tone and vivid saturation. That rare blend of characteristics is recognized as the best of the best, and large gems command those astronomical five and six-figure per carat values. 

Origin Is Also Important To Determine Ruby Value

There are a few species of gemstones, including rubies, whose geographic origin can factor into their ultimate valuation. Origin matters the most for high-quality, impressive stones that have traits that are associated with their host mine.

However, the geographic origin of most rubies does not affect their value because most rubies from the various mines look the same. After they are mined and faceted, most of the small commercial and middle-range rubies are gathered into parcels and sold as lots. When a seller purchases one of these batches, there is often no record of which countries have contributed. It is therefore impossible to know where they were mined.

The Location of the Mine Matters

How does origin significantly impact valuation for high quality rubies? It is due to the mine's reputation. Mines, deposits, regions, and countries may make a name for themselves in two ways: historical importance and distinctive physical properties.

First, the mines that have proven themselves trustworthy in producing beautiful stones over many years, sometimes centuries, can be more desirable than similar gems from mines with less renown. This is a concept that has a significant parallel in modern life. Perhaps you have heard the term "brand loyalty"? This term describes how most people - when presented with multiple products that have similar functions - will most often choose the item they have used in the past. Based on familiarity alone, many shoppers will pay more to get a familiar product rather than risk buying something new. It is the same in the gem world.

Let's say a king, religious leader, or other celebrity figure purchased rubies from a seller with gems from a specific mine. At that moment, a precedent has been set and a reputation established. Subsequent buyers will follow this precedent, further cementing the reputation of the gem deposit. This concept of "brand loyalty" holds especially true for gemstones of the highest quality. 

Where in the Earth A Ruby Forms Also Matters

Second, certain gemstone deposits contain stones with recognizable features. Depending on the desirability of those features, this may attract or repel buyers which, in the end, affects value. When a mine or geographic location gets the reputation of having "better" or "worse" material, the value of all of the inventory is affected. 

Rubies are a rare gem that require very specific, and very unusual, environmental conditions to grow. Corundum is an aluminum oxide mineral. Aluminum and oxygen are abundant in the Earth's crust, so that isn't a problem. The trick is that silicon, another very common element, must be at least mostly absent for the gem to form. Proper heat and pressure levels must also be met. As a result, rubies are only found in a few places worldwide. 

Compounding this issue is the fact that corundum is an allochromatic gem that owes its color expression to trace elements. Even minuscule differences in the concentration of impurities have a noticeable impact on the appearance of gems. The red of rubies comes from the presence of chromium. The more chromium present, the more striking the color saturation. Other impurities, such as iron, affect the expression of the three different aspects of color. Subtle differences in the unique chemistry of various deposits sometimes lead to location-specific characteristics. 

While there is certainly significant overlap in the appearance, chemical makeup, and clarity features of rubies in general, some regions have become known for certain traits. Over time, these location names came to be used as trade terms that describe the color of a gem regardless of their actual geographic origin. This is something to watch out for! The value of two gems whose color is described by the same trade name may have different values if only one of them is from that actual source. If a seller offers you a ruby and uses a geographic name to describe it, check the grading report to see if it lists a confirmed origin location. If it lists origin as "inconclusive" or doesn't mention it at all, you know that the seller is using the description to refer to color alone.  

With respect to rubies, there are five location names that have made this jump to become color trade terms. They are "Burmese", "Thai/Pailin", and "Ceylon/Sri Lankan".

• Burmese - The first location on our list must be Burma due to its deep history and continued economic importance. Originally, the term "Burmese ruby" did reference specifically rubies from the Mogok region of Burma, which is a territory in modern-day Myanmar. Mined since the fifteenth century, the best rubies from Mogok became recognized for their unparalleled beauty, having that magical combination of red or slightly purplish red color coupled with a medium-dark tone, vivid saturation, and fluorescence which made the gem glow. They also often have clouds of rutile silk inclusions which make the color expression appear attractively velvety. 

Over time, rubies were found in other deposits that had similar coloring as the finest Mogok gems. This eventually led to an expansion of the term to include these look-alike stones from other places. You may hear these gems alternatively referred to as "pigeon's blood rubies". 

Remember to check the grading reports for Burmese rubies! A gem that was mined in Mogok will likely have higher value than a similar looking gem from a different location. 

• Thai/Pailin - Corundum mines have been active in Thailand just as long as their Mogok counterparts, but the deposits are significantly more plentiful than the Burmese mines. While the absolute finest of the Thai stones are as beautiful as the gems mined in Mogok, most stones tend to have a darker tone, markedly decreased fluorescence, and no rutile silk. Heat treatment is applied to most stones to brighten and improve color expression, adding value. 

Pailin, Cambodia borders Thailand and houses gems from the same geographic source. Because it is the same deposit, Pailin gems are mostly indistinguishable from their Thai siblings. However, differences in the political atmosphere between the countries makes mining in Thailand a far more advanced art than the more primitive methods used in Cambodia.

• Sri Lankan/Ceylon - Corundum has been actively mined in Sri Lanka, formerly Ceylon, for thousands of years. However, red rubies are relatively scarce. Do you recall reading earlier in this article that it is tone that dictates whether a gem is a ruby or pink sapphire? That is very much an issue with Sri Lankan gems because most of their red/pink corundum has a very light tone. As a result, many of the sellers there put the line between red and pink much closer to pink than other countries and grading labs so that their inventory is worth more.

We should mention that there are other geographic locations, particularly in Africa, along the Himalayan mountains, and East Asia which house rubies, but the names of these sources are not used as trade names to describe color.

Treatment Can Also Impact Ruby Value

Treatments can have a substantial impact on the value of gems at the top tier of the market. For example, the best auction house rubies that are untreated fetch twice the price of a similar, treated ruby. The reality, though, is that most rubies, even some high-quality gems, are treated in some way to improve color and/or clarity.

The most common treatment you will see applied to rubies is heating. This treatment can be extremely beneficial for corundum of all colors, which is why it is widely accepted in the trade and most often does not affect valuation. Heating intensifies color saturation, removes or adds tone as needed, evens out color distribution, and minimizes or even erases unattractive clarity features. Corundum tolerates heat so well that some gems show no signs of being heated, even on a microscopic scale. 

While heat treatment is completely fine for most rubies, other treatments will decrease the value of gems. The reason for this is that heat works with the stone to enhance its appearance while other treatments introduce material that masks, but doesn't fix, detrimental characteristics. Some examples of these treatments are fracture-filling as lattice diffusion. 

Briefly, fracture-filling is a technique that involves soaking a gem in an oil, resin, or epoxy substance of some kind to fill in cracks in the gem. The filler may be colorless or colored. This treatment makes it impossible to evaluate the durability and quality of the gem because it hides the fractures and, if the filler is colored, will artificially intensify the color of the gem. Additionally, no filler material is permanent. It will discolor and dry out over time. It may also melt out of the stone when it is exposed to heat.

Lattice diffusion is a type of extreme heat treatment where a pale gem is heated to the brink of it's melting point. This allows external chemicals - in the case of rubies, chromium or beryllium - to seep into the surface layer of gems which introduces color. 

Clarity Is Also A Factor To Determine Ruby Value

Discussing clarity in regards to corundum is slightly more complicated than with other gemstone varieties because not all inclusions devalue it. Quite the contrary, some features actually add value.

Let's start with the easy part of this subject - the negative clarity characteristics. No one wants to pay for a gem that has a large, dark spot right under the table facet. Gemologists have a term for features like this - eye-visible inclusions. Most (but not all) eye-visible inclusions seriously impact the value of stones both because they are unsightly and can affect the overall durability of gems. 

Rubies can have sparkling, eye-clean clarity. Even average rubies can be expected to be at least mostly eye-clean thanks to heat treatment. Top-quality gems are naturally free of even microscopic inclusions. 

Now, the exception. There is a type of inclusion that adds value to rubies - perfectly oriented rutile silk. Rutile silk is a delicate, microscopic inclusion that looks like tiny pale needles. The presence of clouds of rutile silk can make the color expression of the stone appear smoother and velvety and it boosts the per-carat value of rubies. They are frequently found in Burmese rubies but are sometimes seen in gems from other deposits. 

Microscopic clarity features can be helpful to gemologists valuing gems because some react to treatment in predictable ways. Altered inclusions may be the only clue that a gem has been heated. Unfortunately, rutile silk is dissolved by heat. So, if a gem has clouds of rutile silk, it means that they have not been heated. 

How Size Affects Ruby Value

Bigger rubies are rare, and, therefore, valuable. No surprise here! The best rubies with the most highly desired characteristics rarely exceed one carat in weight. As such, prices for these gems climb dramatically with even fractions of a carat of increased weight. Alternatively, commercial and middle-level stones can grow to be quite large, so the price difference between a smaller gem and a larger one isn't as pronounced. 

A Final Note on Ruby Value

For centuries, people have valued rubies for their deep red color and durability. The ancient Hindus connected rubies with reincarnation, while the Bible associates them with wisdom. Ancient warriors wore the gem into battle believing that the blood-colored stone would give them added physical strength. 

When you combine this historical love of rubies with the high prices they currently fetch, it should come as no surprise that valuers have developed a very specific checklist of characteristics to consider. The factors that have the most influence on the ultimate per-carat value of rubies are their color, origin, treatment, clarity and size. Check out the IGS Gem Price Guide for more information on ruby prices.