The beauty, rarity and historical mystique of rubies are undeniable. The earliest record for the mining of rubies goes back to more than 2,500 years ago in Sri Lanka. The ancient Hindus were enchanted by the color of rubies and they considered them to be the Rajnapura or “King Of Gems”.

Above all other gemstones, including diamonds, rubies command the greatest per Carat prices. For example, the 15.97 Carat faceted Mogok ruby that sold at Sotheby’s in New York, October 1988, fetched a staggering $3,630,000 or $227,301 per Carat.

Understanding where the value lies in rubies is essential to making a rewarding purchase. Not all rubies are the same, and as with all other gemstones, quality equals value. Consequently, there are numerous attributes to consider when selecting this most precious of gems.

Color Is The Most Important Factor In Determining A Ruby’s Value

Identical in every attribute to sapphire, except for their red color hues, the term “ruby” can only be applied to the red varieties of the mineral known as corundum, which is second only to diamond in hardness.

Color is the single most important factor in determining a ruby’s value. As if to emphasis this point, even the name ruby is derived from the Latin word for red ruber. While color preferences are subjective, traditionally the ideal ruby color displays the intensity and richness of bright crimson without appearing too light or dark. Still beautiful within their own right, rubies that appear dark and garnet-like, or those that are light in color and are perceived as pink, generally offer the consumer better value.

It is generally recognized that the best ruby colors possess a captivating, intense, almost electric red effect due to fluorescence. Appearing super-charged, these intense colors are most often seen in Mogok rubies.

The Carat Weight Of Rubies Greatly Affects Per Carat Prices

Large rubies of high quality are the rarest and most highly prized of all gemstones. Rarer than diamonds or sapphires of an equal quality and size, any high quality piece above five Carats is considered to be extremely rare and is almost priceless.

As the Carat weight of a ruby increases, so does its price per Carat. As large rubies are many times rarer than smaller rubies, per carat prices increase disproportionately - a three Carat ruby is worth many times more than three one Carat rubies of a comparable quality.

Prices for ruby increase in stair-like steps when in excess of certain significant Carat weights. For example, a 2.02 Carat ruby commands a higher per Carat price than a 1.98 Carat ruby, despite a negligible difference in actual size. Ruby pricing, like that of nearly all other gems, suffers from a “non-linear-scale of increments”.

Freedom From Inclusions

Ideally, a ruby should allow the free transmission of light throughout its body without hindrance. Quite literally, the ideal is “crystal clear”. However, in reality the clarity found in rubies tends to be less than that found in sapphires and most other gemstones. Classed by the GIA as a Type II Colored Gem, this habitual clarity moniker for ruby means: “in the marketplace these gemstones are usually included”.

High clarities and freedom from inclusions adds value to rubies. Occasionally, evenly distributed, small quantities of microscopic “silk” act like a fine dust, creating a soft, silky, uniform distribution of light throughout the ruby, enhancing both beauty and value.

Shape & Cut

Faceted rubies (those with flat polished faces) are found in a variety of shapes and styles. While ovals and cushion cuts are most commonly seen, other shapes such as emerald cuts and hearts are not uncommon.

Slight premiums are levied upon round cut rubies due to the usually higher carat weight loss of expensive rough crystal during cutting. Conversely, discounts are often applied to the value of both pear and marquise cuts.

A perfectly cut ruby should exhibit good symmetry and polish conditions: facets should be aligned straight in relation to the gem’s girdle and also to each other, polish condition should be good with no visible surface pits or polishing lines.

It could be argued that cabochons are the most common form of cut seen in ruby. Often used to develop and display asterism in star rubies, cabochon cuts are most regularly applied to those rubies whose clarity is not ideal for faceting. Well-cut proportioned cabochons with good symmetry, which are semi-transparent with smooth un-cracked domes, are the ideal.

Classical Sources Of Ruby

The classical source of quality ruby throughout history is the Mogok Stone Tract in Upper Burma. So synonymous are Burmese rubies with fine qualities that the possession of this historical pedigree means that some people are prepared to pay a premium for them over rubies from all other sources.

History aside, rubies of equal quality have been found in Afghanistan, Cambodia, China, Kenya, Madagascar, Pakistan, Tanzania, Thailand and Vietnam.

A specialist prepares the heating
mechanism for the oven.

The Use Of Heat

Most rubies seen on the market today have been subjected to high temperatures in an age-old practice that is said to have originated in Sri Lanka some 2,000 years ago.

Rubies are heated at high temperatures to improve their clarity and to intensify their colors. Without this practice, we would see fewer rubies on the market today, at far higher carat prices due to restricted and narrowed supplies. Heating rubies makes otherwise expensive gems, more accessible and more affordable.

The proportion of unheated rubies on the market is very small and is widely thought to be less than 0.5%. Although no more beautiful, their rarity makes them highly collectable and prices are set at a premium, sometimes fetching triple the price paid for an equivalent heated ruby. When purchasing high quality rubies, please be aware that unheated material is almost non-existent, as a result, always purchase from a reliable supplier who guarantees their gemstones or have the seller’s claim verified by a qualified expert.