Few gems have held our attention over millennia as well as sapphire. The pure blue colors and excellent durability of this gem-quality member of the corundum family make for an exceptional gemstone. However, not all sapphires are blue. The September birthstone comes in every color of the rainbow. Except red.

Color is the most important element in estimating the value of blue sapphire. Although hue counts, the closer to a pure blue the better, saturation is more important. Top sapphires reach vivid saturation. (Many sapphires on the market are actually grayish). Tone is also an important consideration. Dark sapphires are abundant and never reach very high values. (Of course, the same can be said for all dark gems: too dark and they’ll only be moderately valuable). The pictures below are a rough illustration of differences in blue sapphire saturation. After blue, pink and pink-orange padparadscha colors command the highest prices.

All red, gem-quality corundum gems are considered rubies. All other colors of gem-quality corundum are considered sapphires. On the market, blue sapphires are usually simply called sapphires, while sapphires of other colors are commonly specified as yellow sapphires, pink sapphires, etc, and are collectively known as “fancy sapphires.” However, when discussing the physical and optical properties of sapphires, the term “sapphire” applies to all sapphires regardless of color.

Sapphires get their extraordinary colors from trace elements such as iron, titanium, chromium, and others. Traces of vanadium may cause color change in some sapphires. These sapphires show one color in daylight or fluorescent light and another in incandescent light.

Pink Sapphire or Ruby?

There is some disagreement about the distinction between pink sapphires and rubies. Some authorities classify only corundum gems with a dominant red hue as ruby. Others consider any red corundum, including pink, which is a light tone of red, to be ruby.

What is a Padparadscha Sapphire?

Debates over colors and definitions extend to padparadscha sapphires, too. Subjective descriptions of these “lotus-colored” sapphires include “sunset,” “peach,” and “salmon.” The preferred color qualities range from a light to medium-tone orange-pink to pink with a slight orange hue to orange with a slight pinkish hue to a more deeply saturated orange-pink. These preferences also vary between consumers from Eastern and Western countries.

The Lore and Lure of Sapphires

For centuries, sapphire has been popularly associated with royalty and said to protect against poison and fraud. Star sapphires have also been associated with the power to divine the future. However, ancient references to sapphires may actually refer to lapis lazuli, another striking but gemologically distinct blue stone.

Luminescence

Natural Blue Sapphire Fluorescence

Typically, natural blue sapphires have no reaction to ultraviolet light (UV). However, there are some notable exceptions:

• Some blue Thai sapphires fluoresce weak greenish white in shortwave (SW) UV.
• Sri Lankan blue sapphires may fluoresce red to orange in longwave (LW) UV and light blue in SW.
• Blue color-change sapphires may show a weak, light red fluorescence in SW.
• Some African blue sapphires may show moderate to strong orange fluorescence in SW.
• Heat-treated blue gems sometimes fluoresce chalky green in SW.

Natural Fancy Sapphire Fluorescence

• Green sapphires: inert.
• Black sapphires: inert.
• Sri Lankan yellow sapphires: fluoresce a distinctive apricot color in LW and X-rays, and weak yellow-orange in SW. The fluorescence in LW is proportional to the gem’s depth of color.
• Pink sapphires: strong orange-red in LW, weaker color in SW.
• Violet or alexandrite-like sapphires: strong red in LW, weak light red in SW.
• Colorless sapphires: moderate light red-orange in LW.
• Orange sapphires: a strong orange-red in the presence of LW.
• Brown sapphires: usually inert or weak red in LW and SW.
• Natural color-change sapphires: inert to strong red in LW, inert to moderate red to orange in SW.

Sapphire Trade Names

Please note: you may find these names used purely as descriptive terms. Sapphires can’t always be identified by their color alone. Always confirm the origin of a sapphire with a vendor, especially if the gem is sold with a “geographic” name. Ask if the name refers to the actual origin or simply the color.

• Adamantine spar: brown, usually opaque but may be translucent to transparent.
• African: usually light in tone.
• Australian: usually very dark, some yellow and green parti-colored.
• Burma or Oriental: slightly violet-blue, highly saturated, medium to medium dark tone.
• Cashmere or Kashmir: velvety, slightly purplish blue, strong to vivid saturation, medium to medium dark tone.
• Ceylon or Sri Lanka: light to medium tone, slightly grayish to violetish blue.
• Geuda: milky stones from Sri Lanka that can turn blue as well as yellow or orange when heated.
• Montana: all colors, usually light to medium tone, grayish saturation.
• Padparadscha: “lotus flower” color,” pinkish orange.
• Thai or Siamese: dark blue.

Sapphire Care

Sapphire’s hardness is second only to diamond among natural gems. It also has no cleavage planes. This makes it a superb jewelry stone. Of course, a heavily included or fractured stone will be less stable.

For reasonably clean stones, no special wear or care precautions are necessary. However, avoid cleaning any oil-treated sapphires with ultrasonic systems. Otherwise, you can clean sapphires with mechanical systems. Nevertheless, cleaning your sapphires at home with warm water, detergent, and a soft brush or taking them to a professional jeweler are your safest choices.

Besides blue sapphire and ruby, the corundum family also includes so-called “fancy sapphires.” They come in violet, green, yellow, orange, pink, purple, and intermediate hues. There are also “parti-colored” sapphires that show combinations of different colors. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can even be gray, black, or brown.

Fancy sapphires are generally less available than blue ones, and some colors are scarce, especially in very small or very large sizes. Still, fancy sapphires create a rainbow of options for people who like the romance associated with this gem, but who also want something out of the ordinary.

The mineral corundum is composed only of aluminum and oxygen, and it requires a growth environment that’s free of silicon. However, silicon is a very common element, making natural corundum relatively uncommon. In its purest state, corundum is actually colorless. Colorless sapphires were once popular diamond imitations, and they’ve staged a comeback as accent stones in recent years.

But colorless corundum is rare. Most corundum contains color-causing trace elements. When the trace elements are iron and titanium, the corundum is blue sapphire. Only a few hundredths of a percent of iron and titanium can cause the color, and the more iron the corundum contains, the darker the blue. Chromium can cause the red color of ruby or the pink of pink sapphire.

In the 1990s, discoveries in East Africa and Madagascar brought fancy sapphires widespread recognition. The new sources supplemented production from traditional ones like Sri Lanka and Madagascar and increased the availability of yellows, oranges, pinks, and purples.

The colors attracted jewelry designers who wanted to move away from traditional hues of red, blue, and green. Now, contemporary designers arrange fancy sapphires in stunning rainbow suites.

Corundum can show a phenomenon called asterism, or the star effect. This phenomenon usually appears as a six-ray star pattern across a cabochon-cut stone’s curved surface. The star effect can be seen in ruby or any color of sapphire, and it arises from white light reflecting from numerous tiny, oriented needle-like inclusions.

Besides fancy sapphire and star corundum, there’s another interesting variety: color-change sapphire. These fascinating stones change color under different lighting. Their presence adds a special dimension to the already amazing corundum family of gems.

Both blue and fancy sapphires come from a variety of exotic sources including Madagascar, Tanzania, Sri Lanka, Myanmar, and Australia.

(From GIA)