Sapphire Buying Guide
Sapphire’s high hardness means it’s very resistant to scratching. Thus, it makes an excellent jewelry stone for any occasion. These gems also show pleochroism, two different colors when viewed from different angles. In rare cases, mineral crystal inclusions can create star sapphires, specimens that display a “star stone” effect known as asterism. Some rare gems can also change color, depending on the light source.
However, since gem-quality natural sapphires are rare and the demand so great, you’ll commonly find synthetics and imitations on the market. They also frequently receive treatments and enhancements for the same reasons.
What is a Sapphire?
Gem-quality corundum falls into two categories: ruby or sapphire. All red corundum gems (however defined) are considered rubies. All other colors are considered sapphires. Thus, sapphires occur in every color except red.
Commercially, blue sapphires are commonly referred to as simply sapphires. This reflects not only the persistent cultural association of sapphire with the color blue but also the consumer demand for blue sapphires. You may find sapphires of other colors referred to as “fancy sapphires,” as in our IGS Sapphire Value Listing. Nevertheless, all sapphires are non-red corundum gemstones. When discussing optical and physical properties, “sapphire” refers to all sapphires regardless of color.
Sapphire Buying and the Four Cs
The International Gem Society (IGS) Sapphire Value Listing has price guidelines for sapphires from various sources with different color and clarity grades, sizes, and cut styles. For an introduction to gemstone grading in general, see “A Consumer’s Guide to Gem Grading.”
Color plays the greatest role in determining the value of a sapphire gem. Blue sapphires usually command the highest prices.
In the Gemological Institute of America (GIA) color grading system, color consists of three qualities: hue, tone, and saturation. The basic hues include red, orange, yellow, green, blue, violet, and purple. Tone refers to a color’s relative lightness, from colorless (0) to black (10). Saturation refers to a color’s intensity, from grayish or brownish (1) to vivid (6).
In gem reports and price listings like those for sapphires, you’ll find the abbreviations for the dominant hue capitalized. Other hues present aren’t capitalized and may be further described as “sl” for slightly and “st” for strongly. (For more information on gem color codes, see this article).
Top blue sapphire color consists of a hue of violet-blue or blue, a medium to deep tone of 5 to 6, and a vivid saturation, 6. These color grades are noted as vB 5/6, vB 6/6, B 5/6, and B 6/6. Vivid saturation is rare. However, exceptional sapphires may reach this level. Stones with vivid saturation will fetch the highest prices.
Sapphires with dark tones (7 and higher) are relatively more abundant than lighter stones and aren’t valued highly. Sapphires with light tones are referred to as “steely.”
Kashmir sapphires are the most highly prized. A sapphire from Kashmir will be valued higher than an equally graded stone from another source.
What Makes a Blue Sapphire?
Blue sapphires must contain a strong element of blue, although the blue can include violet or even green hues. Violet stones or bluish-violet stones are still considered blue sapphires. Thus, you may see them sold as simply “sapphires.” However, green dominant stones with blue hues normally won’t be sold as sapphires without a color qualification. Most consumers find the violet secondary hues more attractive than green. Therefore, sapphires with either pure blue hue or a violet secondary hue command higher prices than those with green secondary hues.
Purple and Green Sapphires
Once a stone becomes dominant purple in hue, it becomes a purple sapphire. Likewise, once the color crosses into dominant green, the stone becomes a green sapphire. While purple and green sapphires cost much less than blue sapphires, they’re still fairly expensive. However, they don’t enjoy much consumer demand. People looking for purple gems evidently prefer much more affordable amethysts. Green sapphires tend towards desaturation, Thus, they’re neither popular nor highly valued. Lapidaries often slice them to use as caps on assembled synthetic sapphires.
After blue, pink is the most highly valued sapphire color. Padparadscha sapphires, pink-orange gems from Sri Lanka, are especially prized.
Clarity refers to a gem’s transparency and anything that can impact how it transmits light. All corundum gems, including sapphire, are Type II gems in terms of clarity. That means sapphires usually contain inclusions. These are fractures and materials such as liquids, gases, and even crystals of other minerals inside their structure. For example, part of the appeal of Kashmir sapphires is their velvety appearance, caused by inclusions of very fine threads of rutile crystals known as silk, which scatter light. Other sapphires with rutile or hematite inclusions may display a star effect.
Top Tier Clarity
Top tier values for sapphires of the same color grade go to stones with clarity grades of VVS (very very small inclusions), or what gemologists refer to as loupe clean. This means that even when examined with a 10X loupe, no inclusions can be detected. These gems are, of course, also eye clean. Loupe-clean sapphires require microscopic examination in order to identify the nature and character of any inclusions.
Since loupe-clean sapphires are so rare, especially in larger sizes, a buyer should be extremely cautious and seek the counsel of a reputable gemology laboratory to verify natural origin and lack of treatments before purchasing. There are no “deals” to be had in fine sapphire. If it seems too good to be true, it almost certainly is. Finding a sapphire of this quality, in any size over one carat, irrespective of price, is a challenge.
Second Tier Clarity
The second tier of value for sapphires of the same color grade are stones that are clarity graded VS (very small inclusions) but still eye clean to SI (small inclusions), which may very well not be eye clean. In both instances, inclusions are numerous and/or large under a 10X loupe or are eye visible. The prominence of inclusions visible to the naked eye is the primary driver of value within this tier. If inclusions are prominently visible to the naked eye from any viewing distance, the stone’s value drops dramatically. Most commercially available “gem-quality” sapphires fall somewhere within this second tier.
Third Tier Clarity
The third tier of value for sapphires of the same color grade are stones that are clarity graded SI to I (included) — clearly “not eye clean.” These eye-visible inclusions may have a moderate effect on durability, and/or may be so prominent that the stone isn’t suitable for use in jewelry. These sapphires are plentiful.
Although cutting usually has the least impact of the 4 Cs on the value of colored gemstones, the quality and choice of cut does affect the value of a sapphire.
Cuts that maximize light return, such as brilliant cuts, or those that enhance color, such as step cuts, are recommended. Emerald and marquise cuts add the most to a sapphire’s value, followed by round and pear cuts. Common cuts for sapphires include ovals and cushions.
A cabochon cut can make a sapphire with the right arrangement of rutile crystal inclusions display a lovely asterism or “star stone” effect. Cabochons can also be used for sapphires with inclusions that would be considered too unsightly for faceting.
The price per carat of sapphires increases gradually at carat sizes of 2, 3, and 4. As opposed to rubies, high-quality smaller sapphires aren’t uncommon. However, sapphires over 5 carats are rare and will see a jump in price per carat.
Sapphire Buying and Jewelry Uses
A vivid blue sapphire makes a powerful statement, but there are enough color variations of sapphire to let you make an individual statement at many price levels. For example, a top color 1-ct blue Kashmir sapphire may cost as much as $22,650. A top color 1-ct purple sapphire, on the other hand, may cost as much as $570.
You can learn to live with sapphires that have eye-visible inclusions. Eye visible means visible at a distance of approximately 6 inches. That’s very close. Clarity grades of VS to SI bring a significant reduction to sapphire prices. A top color 1-ct blue Kashmir with a clarity grade of SI to I may come down to $9,000. The same color grade stone with a VVS clarity score could cost up to $22,650.
A sapphire with a clarity grade of I or lower can still make a beautiful piece of jewelry. It just needs to be worn in an appropriate setting. A stone with inclusions that affect wearability may not be a good choice for a ring or bracelet. However, it might do very well as a pendant or earring. (These stones still resist scratching but may suffer damage from contact blows).
Sapphire Origins and Trade Names
A sapphire’s host rock typically determines its color. Sapphires are found all over the world, and the combinations of trace minerals found at their sources lead to subtle variations. For example, non-basaltic rock such as marble or limestone typically produces sapphires with more brilliant hues. On the other hand, basaltic rocks contain high amounts of iron, which darkens the color of the stones. Sapphires from Thailand, Cambodia, Australia, and Madagascar tend to occur in basalt, whereas Montana sapphires form in a type of igneous rock.
Sapphires may receive regional names, such as “African,” “Australian,” “Burmese,” or “Kashmir,” because they were mined in that region or exhibit characteristics, such as color, associated with stones from that region. Thus, you’ll sometimes encounter sapphire colors also associated with regions, such as “Burmese” or “Oriental” slightly violet-blue or “Thai” dark blue. However, color alone isn’t enough to accurately identify the source of a sapphire. Don’t assume that sapphires with regional trade names necessarily originate from those areas.
Here’s an overview of characteristics associated with stones from the following regions.
Kashmir sapphires are legendary. Often exhibiting “cornflower” blue, a strong to vivid, medium-dark violetish blue to pure blue, they set the color standard for sapphires. Their renowned velvet glow intensifies their color. Since the Kashmir mines dried up over a century ago, Kashmir sapphires are nearly priceless.
Burmese or Myanmar Sapphires
Like Kashmir sapphires, violetish blue to pure blue Burmese sapphires have strong to vivid saturation and medium to dark tone. Their color, known as “royal” blue, can have even greater saturation than that of Kashmirs. However, Burmese sapphires lack Kashmirs’ velvet luster and can sometimes appear dark or inky under incandescent light. Nevertheless, these exceptional sapphires still command high prices.
Ceylon or Sri Lankan Sapphires
Sri Lankan sapphires have the same hue as Kashmirs and Burmese but tend to have slightly weaker saturation and much lighter tone (medium-light to light). Therefore, they have more brilliance (light return) than those sapphires, although their blue color may not be regarded as fine.
The majority of Montana sapphires have pale or steely blue-gray colors. They require heat treatment to gain an attractive color. However, sapphires from the Yogo Gulch, Montana deposit are known for their beautiful “cornflower” blue color, even without heat treatment. Yogo Gulch sapphires tend to come in sizes of half-carat or smaller. Those who want a large Yogo Gulch sapphire will have to pay a premium.
Cambodian or Pailin sapphires range from violetish to very slightly greenish blue, with medium to dark tone. Their dark tone makes them well suited for melee (less that ¼ carat), since they remain saturated in smaller sizes. However, they may appear too inky to be attractive in larger sizes.
Thai and Australian Sapphires
Kanchanaburi sapphires look similar to Sri Lankan sapphires but lack their brilliance. They can sometimes appear grayish when desaturated. Most of them also look a bit milky.
Thai and Australian sapphires tend to be dark and are described as inky or blue-black. Their dark tones hide their color and brilliance. Australian sapphires also often show strong green and blue pleochroism. This means that they can appear strongly blue from one angle but strongly green from another.
Beware of Sapphires with Two Names
Merchants use many legitimate trade names to market sapphires. Unfortunately, sometimes unscrupulous vendors may attach the name “sapphire” to less expensive gemstones to appeal to unwary consumers. This holds true particularly for less expensive blue gems, due to sapphire’s strong association with blue. For example, you might find blue tourmalines referred to as “Brazilian Sapphires.” Furthermore, this same association with blue means some consumers are unaware of sapphire’s other possible colors. Thus, some vendors wrongly promote fancy sapphires by associating them with gemstones with other strong color associations. For example, yellow sapphires sometimes appear for sale as “King’s Topaz.” Of course, sapphires, tourmalines, and topazes are different gem species.
Other expensive and well-known gemstones also occasionally find their reputations used to mislead consumers. See our articles on “Serengeti Rubies,” “White Aquamarines,” and “False or Misleading Gemstone Names” for more information.
Sapphire Buying and Phenomenal Effects
Sapphires can exhibit two very stunning phenomenal effects: color change and asterism. As a general rule, color change sapphires are more expensive than star sapphires but less expensive than regular faceted sapphires. Of course, this also depends on the overall quality of the stones.
Color Change Sapphires
Some sapphires change from a cool to a warm color when taken from daylight or fluorescent light into incandescent light. Vanadium trace elements cause this change, which usually goes from blue or violet in daylight to violetish purple or reddish purple in incandescent light. A few rare sapphires change from green to reddish brown. The stronger the color change in hue and intensity, the more the stone’s worth increases. For those looking for unusual jewelry stones, color change sapphires make a great choice. They’re incredibly rare and can sometimes resemble alexandrite at a fraction of alexandrite’s cost.
Asterism occurs when inclusions in sapphire create intersecting bands of light that roll across the stone. This effect makes the stone appear as if it has a star floating across it. (You can see a similar effect with a band of light running across a spool of silk).
When cutters come across a sapphire with a great deal of needle-like inclusions, they can either cut the stone into a cabochon to enhance the star or heat the stone to remove the inclusions and facet it. In most cases, faceted sapphires command higher prices than cabs, even those with stars. However, if the sapphire has very good color and a crisp, strong star, cutters may elect to preserve the star.
Black Star Sapphires
If hematite inclusions create the star effect, the sapphire will appear black. Black star sapphires are more common and less valuable that blue sapphires. They’re also prone to parting along twinning planes.
Star Sapphire Quality Factors
Most star sapphires have six points. A few will have four or even twelve.
In terms of value, the more well defined the star, the higher the stone’s worth. Ideally, the star should also be centered and have arms of even length that roll smoothly across the stone. On the other hand, a star too crisp and centered may indicate a synthetic stone or asterism induced through lattice diffusion, or both.
Sapphires have been created in laboratories for over a century. Modern techniques can create gemstones that can challenge even experts to distinguish them from natural. The presence of undisclosed synthetics in the marketplace is just one of the things the wary consumer needs to keep in mind.
Synthetic sapphires are real sapphires. Chemically and physically they may appear indistinguishable from natural sapphires. This is no consolation, however, if you’ve unknowingly purchased a synthetic sapphire at natural sapphire prices. A synthetic sapphire only costs a few dollars a carat, whereas a natural sapphire of the same quality will cost thousands to tens of thousands of dollars per carat. (In 2015, a customer filed a lawsuit against the jewelers who sold him a $9,000 pink sapphire in 1999 that turned out to be a $30 synthetic stone).
Your best defense against purchasing an undisclosed synthetic is to have the sapphire appraised by an independent gemology lab. Sapphires are very valuable gems. Thus, merchants have a great incentive to treat gems to improve their appearance and to sell synthetics. Consumers should be aware of treatments and synthetic origins, because these factors impact not only care but also price.
Indications of Synthetic Origin
Synthetic sapphire may appear just too perfect to be natural. They may have a combination of extraordinarily vivid coloring, strong fluorescence, and high clarity. However, synthetics tend to receive poor polishing. They’re not worth the time and labor needed to give them a refined polish.
The single most recognizable indicator of synthetic origin is curved striae within the stone. Natural sapphires will never show these clear, curving parallel lines. Rather, they’ll show angular lines as part of their natural hexagonal crystal structure.
If you’re searching for curved striae, keep in mind that polish lines may look like curved striae. However, polish lines occur only on the surface of a stone and vary in direction from facet to facet. Curved striae occur within the stone and extend across it. You can see them more easily back lit while rocking and tilting the stone.
Heat treatments are commonly applied to sapphires to remove rutile inclusions and improve color tone and saturation. Melting these inclusions within the stone releases titanium, which intensifies blue hues. 95% of sapphires are heated. Thus, always assume a sapphire is heated unless told otherwise. Merchants with unheated sapphires will always be eager to inform their customers, because such stones command incredibly high prices.
Heating can be done with anything from rudimentary clay crucibles placed in metal drums to high-tech, temperature-controlled kilns. This process can be hit or miss. The colors aren’t guaranteed to come out as expected. However, results are stable and permanent.
How to Detect Heat Treatment
Confirming sapphire heat treatment can be tricky. You can use a loupe to check for melt relics. These may include: hazy clouds of dissolved rutile needles; melted, blobby-looking crystals; white tension halos around melted crystals; and bumpy girdles on faceted gems that look slightly melted. (These telltale bumpy girdles are often polished away).
Intact rutile needles almost always indicate a natural, unheated sapphire. Since rutile has a low melting point, it will melt if the stone is subjected to significant heat.
If a sapphire has been heated, it is most likely natural. However, some dishonest gem dealers will heat synthetic stones to give them melted girdles, so consumers will mistake them for heated naturals. Heating a synthetic stone also diminishes the appearance of curved striae, the hallmark of a synthetic stone.
For more information on these and other treatments applied to sapphires, see our article on corundum treatments.
Sapphire Buying as an Investment
If you think you’ve found sapphires at a bargain price and are considering making a purchase for investment purposes, read this article on investing in gemstones.