Spinel Buying Guide

by Donald Clark, CSM IMG; Barbara Smigel, PhD GG

Natural spinel has long been overlooked. Superstars of the gem world with a similar appearance, like ruby and sapphire, as well as commonplace synthetic versions have taken its spotlight, so to speak. Now, spinel has become a popular gemstone in its own right. The colors of natural spinel can rival ruby red or sapphire blue. These gems are also available in many other colors and at broader price ranges than their corundum competitors. Our spinel buying guide can help you choose the right stone for almost any jewelry use.

Spinel Buying And The 4 Cs

Although red and blue colored spinels command the highest prices, clarity and carat can also have a significant effect on value. Myanmar (“Burmese”) provenance always adds value.

The IGS spinel value listing has price guidelines for spinel buying with different color grades, sizes, and cut styles.

Color

In the GIA color grading system, color consists of three qualities: hue, tone, and saturation. The basic hues are 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). The dominant hue is capitalized. Other hues present are not capitalized and may be further described as “sl” for slightly and “st” for strongly.

Be aware when spinel buying that saturation or “spectral purity” is the color quality that will have the greatest impact on price. You could easily expect to pay five to ten times as much per carat for the true red stone below on the right as for the less saturated pink one on the left.

Top color for so-called “ruby spinels” consists of a red (R) or purplish red (slpR) hue with a medium tone (5) and a strong saturation (5). Stones with more purple hues (P, rP, and bP) with medium tones and strong saturation are also highly prized. Although top-quality red spinel is actually rarer than top-quality ruby, it’s not as expensive.

Orangey-red stones are known as “flame spinels.” Top colors for these stones consists of an orange (O) or orangey red (rO) hue with a medium tone (5) and a strong saturation (5).

Blue and violet spinels are, in general, more modestly priced, unless their color is highly saturated. Among the blue stones, those colored by cobalt are especially valued for their pure, rich color. Top blue color consists of a blue hue (B) with medium tone (5) and strong saturation (5). Top violet color consists of a violet hue (V) with medium tone (5) and moderately strong saturation (4). In blue and purple hues, spinel is commonly relatively steely/grayish or quite dark in tone. These qualities will depress the value of a stone.

Pink spinels in hues from bubblegum to hot pinks are highly sought.

Color change varieties (from grayish blue in daylight to an amethystine color in incandescent light) are rare in this species and highly valued.

By far the most common, lowest value colors of spinel are pale to medium mauve-pink and light grayish purple.

Clarity

Clarity refers to a gem’s transparency and anything that can impact how it transmits light. All spinels are Type II gems, meaning they are usually included. An inclusion-free spinel or an eye clean specimen will typically have a higher price. However, inclusions will likely not affect the value of a top color stone.

Star spinels, stones with inclusions that create the asterism effect, are very rare and highly valued.

Cut

Spinels can be faceted into many shapes to showcase their vibrant color and brilliance. Popular cuts for transparent crystals include cushion cuts, emerald cuts, rounds, and ovals. Opaque spinels and star spinels are cabochon cut. Opaque black spinels are also faceted.

One of spinel’s most beautiful crystal habits is the octahedron, one of the basic shapes of isometric crystals. (Diamonds also occur in this form). Spinel can sometimes be found at the site of its formation, often in metamorphic rock deposits, in this exquisite, natural shape.

Carat

The price per carat for most spinels jumps at one carat. Fine red gems over three carats are very difficult to obtain. Large spinels of other colors are available from time to time. The price per carat of pink and purple spinels jumps again at three carats. Blue stones jump at four carats. Orange stones jump at five carats.

Spinel Buying: Jewelry Considerations

Spinel is a durable and facetable gem with so many colors that a consumer can likely find a piece for any type of jewelry and occasion. The majority of the spinel jewelry for sale today is in the pink and red color range. This may change as the variously colored African spinels begin to affect the market.

As black diamonds have grown in popularity, so has black spinel jewelry. Black spinel makes a less expensive substitute for black diamond and a more durable, if more expensive, substitute for black onyx.

Spinel beads are rarely available on the market. They are sometimes sold by vendors who specialize in higher grade goods.

Although the rare reds and blues still receive the lion’s share of attention, the more common, less valuable colors are not without admirers. Desaturated mauve-pink spinels have inspired one enthusiast to refer to the color as “Garden of Eden,” since the color matches that of her fancy colored hybrid flowers when left to self-sow and grow wild. With brown, gray, lilac, rose, and nearly colorless varieties in stones ranging from transparent to opaque, there is surely a spinel to pique any consumer’s interest.

Spinel Buying: Synthetics

At present, spinel buying consumers can assume that the natural variety generally is not treated or enhanced. (Although gemologists keep a close watch for new developments). Synthetic spinels, however, are very common. (They are often found on class rings). Colorless spinels are rarely found in nature and are most likely lab-grown. Yellow and pure green stones are also likely synthetics. Highly desired red and blue spinels can be created with the flame fusion method. A professional gemologist can distinguish a synthetic from a natural stone by studying its absorption spectrum through a spectroscope.

Spinel Buying: Origins

Until the 19th century, spinels mined from Afghanistan and Tajikistan were called rubies due to their color. Red and pink spinel is still found in these areas.

Sri Lanka is the principal source of gem-quality spinel on the market today, including the rare cobalt blue variety.

The highest quality spinels have traditionally been sourced in Myanmar (Burma). Unlike ruby and jadeite, spinel is not subject to US sanctions on Myanmar. Burmese red spinels are closest to the prized “blood red” color of rubies.

In 2007, spinels were discovered near Mahenge, Tanzania. These mahenge spinels show neon pinkish red and orangey red colors. They now rival the Burmese material in terms of quality.

Spinels are also found in many locations in the United States.

Spinels have been found in many countries. For more information, see “Sources” under our spinel gem listing.