Ruby Evaluation & Buyer’s Guide – An Overview

Ruby’s beauty and mystique is legendary. Referred to by ancient Hindus as Rajnapura (or “King of Gems”), its enchanting history stretches back more than 2,000 years. In 1988, a 15.97 carat Mogok ruby sold at Sotheby’s for an incredible $227,301 per carat. More recent auctions in Hong Kong by Christie’s, Sotheby’s and Tiancheng yield a ruby price per carat that far exceeds diamond. Rubies are “in”.

When purchasing a ruby it is essential to understand where the true value lies. The ruby quality scale is really a complex matrix of many factors. Not every ruby is equal in quality or price, and we’ll try to cover all the factors you’ll need to keep in mind on this page. The matter of what are rubies worth is directly extrapolated from the aforementioned matrix.

Ruby Color Impacts Value

Color is the only attribute that separates ruby from sapphire. A red variety of the mineral corundum, its hardness  is only exceeded by diamonds. It is its red color though which commands the high price tag. The finest rubies should burn with an intense crimson that is neither too light nor dark. Better values can be had when rubies take on a dark, garnet-like, hue or when the color leans toward pink. Mogok rubies from Upper Burma are especially noted for an electric-like red fluorescence.

Ruby Carat Weight Impacts Per Carat Prices

Some people are surprised to discover that rubies are rarer and more expensive than diamonds of comparable size and quality. When a high quality ruby tops five carats it becomes almost priceless.

As the carat weight increases, so does its price. Large rubies are much rarer than smaller ones. This means that a three carat ruby will carry a price tag many times greater than three one carat rubies of equal quality.

Ruby pricing follows a “non-linear-scale of increments” similar to the pricing of other gemstones. Therefore, a 1.97 carat ruby will fetch a higher per carat price than a 2.01 carat, even though they are close to the same size.

That said, the largest ruby in the world is measured in kilos and there are several that vie for the this slightly dubious crown as they are not gem quality and their value per carat or gram is is comparatively very low.

Ruby Inclusions

Ruby is classified as a Type II colored gem, which means “in the marketplace these gemstones are usually included.” In general, the clarity is less than that found in sapphires. Ideally, rubies should appear “crystal clear” and allow a free flow of light through the body.

Ruby Shapes & Cuts

Rubies are faceted into a variety of shapes, including cushion, oval, emerald, and heart. Due to loss of expensive rough during cutting, round cuts are levied with a premium. Discounts, though, are often given for marquise and pear cuts.

The facets of a finely cut ruby should align straight with each other and the gem’s girdle. No pits should be seen, nor any flaws or polishing lines. When cabochon cut, the gem should be well-proportioned, with smooth un-cracked domes.

3 Carat Unheated 18K Gold & Diamond Ruby Ring by Flames Jewelry™
3 Carat Unheated 18K Gold & Diamond Ruby Ring by Flames Jewelry™

Ruby Origin

Historically, the best rubies were sourced from Sri Lanka and Burma’s famous Mogok stone tract. Today the issue of where where do rubies come from effects both price and market desirability. People pay premium prices for Burmese ruby. But, in reality, rubies just as beautiful as the Burmese and Ceylon rubies are now sourced from Cambodia, Kenya, Madagascar, India, China, and other countries. Unheated Burmese ruby commands the highest premium of all the different types of ruby. Madagascar ruby tends to be slightly darker due to the high iron content.

Exacerbating prices is also the matter of supply that emanates from the Burma ruby mines. The ruling military junta of Burma, or perhaps correctly Myanmar, periodically close the mines which slows output. During these spells, supply is squeezed and somewhat unsurprisingly the Burmese ruby price per carat shoots up and over the previous average per carat prices.


Burmese Ruby

Characterized by a very bright fluorescent red color, Burmese ruby has the pedigree and heritage that none of the the other ruby mines in the world have. A blood red ruby, often referred to as Pigeon Blood Red Ruby is recognized to the be characteristic that all rubies strive for. As a consequence, Burmese ruby value is higher than any other locale in the world, with African ruby prices per carat tending to nearly always be at a discount to their Burmese counterparts.


Madagascar Ruby

Located down in the south.


Mozambique Ruby

Hailing from Montepuez, in Cabo Delgado Province, these rubies have turned the market on their. For a while they labored under the misnomer Niassa Ruby until field gemologist proves they were actually from Montepuez. This new kid on the block deposit is so significant that it really requires its own page. The ruby from Montepuez and the paler that don’t make the grade and are sold as fancy Mozambique sapphire are the most important ruby find in the last 100 years, possibly more.


Indian Ruby

Generally perceived as low quality these deposits produce cabochon type materials and low quality corundum suitable for glass filling.


Songea Ruby from Tanzania

This is a tricky one, and Tanzania songea ruby is arguably not ruby. The mines were discovered in the 1980’s but not really commercially exploited until the mid-90’s. Fast forward to the year 2001 and some observant soul in Chanthaburi, Thailand, noted that songea sapphire turned to ruby and near ruby colors when chrysoberyl was inadvertently left in a heating crucible.

Heating Rubies

The heating of ruby can be traced back 2,000 years to the gem artisans of Sri Lanka. Ruby is heated to enhance clarity and intensify color. This age-old practice makes fine quality ruby more affordable and accessible. Less than .5% of the world’s market-sold rubies are unheated. This unheated stone is extremely collectable and can command triple the price of heated gems. Always purchase unheated rubies from a supplier with a certificate whose claims can be verified.The prices for heated rubies in the ruby wholesale markets varies but is always lower than that of unheated ruby.


Fissure Filled Rubies

Also known as a glass filled or glass treated ruby, these rubies burst on to the scene it two different eras via different chemical processes.

Flux filling

Borax Glass Filling

Rough Ruby

The rough ruby markets are are governed by both supply and demand. The demand comes mainly from ruby factories in Chanthaburi, Thailand. Each ruby producing region produces different qualities and even the crystals shapes and surface features of a rough ruby stone can give away the origin without any need for faceting or placing under a microscope to divine the provenance.

Since the arrival of the Gemfields in to the ruby industry in 2010, most uncut rubys are sold via auction in Singapore to large ruby buyers who have their factories in Chanthaburi, Thailand.

Madagascar ruby bought tends to have a classic corundum crystals shape with attractive terminations and surface striations and trigons. Under the surface but clearly visible with a penlight or even a mobile phone torch is iron dots, which are frequently seen in Madagascar ruby.

Conversely, Mozambique ruby rough tends to have a much flatter more tabular shape with the c-axis being 90 degrees to the broad tablet crystals.