10 Rare Engagement Ring Stones that Won’t Break the Bank

Spinel

Natural spinels are fairly rare, which has kept their prices low. Since they don't exist in large quantities, the average jewelry store doesn't stock them, so most consumers don't know about them.

Spinels come in a stunning array of vivid colors, such as red, orange, purple, blue, and greenish blue. Throughout history, they have also been mistaken for other gemstones. For example, the Black Prince's Ruby and Timur's Ruby, both set in the British Imperial State Crown, are actually red spinels. Red and pink spinels are the most highly valued. Red spinels can appear to have the vivid, glowing color of rubies for a fraction of the price. Lavender and blue spinels are popular as well.

Spinels tend to occur in sizes below two carats. They make wonderful, durable, and rare engagement ring stones with strong dispersion or "fire," which gives them that extra sparkle.

Moldavite

What can you get for a love that's just out of this world? How about a moldavite, an extraterrestrial glass formed from an asteroid impact 150 million years ago? This asteroid struck at a velocity high enough to melt and splatter across what is now Austria, the Czech Republic, and Germany. The materials cooled so quickly they didn't have time to crystallize.

These yellowish green to greenish brown gems are popular both as display specimens and jewelry stones. Like other glass, both natural and artificial, moldavite can be a bit brittle. Therefore, if worn as a ring stone, protect it with a bezel setting or a special design to protect this alien visitor.

Buyer beware! Some unscrupulous dealers may facet imitation "moldavite" from green glass bottles.

Tanzanite

Discovered by Maasai tribesmen in Tanzania in the 1960s, tanzanite is a relative newcomer to the gem scene. When first formed in the Earth, tanzanites appear brown. However, when heated, they turn a brilliant blue to violet color. (Supposedly, a bush fire led to the discovery of the first tanzanites). Tanzanite occurs only within a 4-km radius of the Merelani Hills in Tanzania. A thousand times rarer than diamond, supplies of tanzanite may run out in the next few decades.

Tanzanites have become very popular but rare engagement ring stones. They have distinctive trichroic colors. That means they can show three different colors — blue or violet, purple or red, and greenish-brown — depending on the viewing angle. Some gem enthusiasts see these rich blue, high-clarity stones as affordable sapphire substitutes. Others treasure these gems on their own terms, for their clear sparkle and distinctive flashes of violet.

Please note, tanzanites have a tendency to cleave or split. So, take special care when setting and wearing this stone.

Kunzite

Looking for an engagement ring stone that can represent tenderness? Kunzites have beautiful light pink to violetish purple colors. The most highly valued also have a lot of saturation or "intensity." A variety of spodumene, kunzites can occur in large sizes in Afghanistan, Brazil, Madagascar, and California, and collectors in the US and Japan prize them as display pieces. These gems can also make stunning jewelry pieces.

However, kunzites are truly delicate beauties. Their colors can't bear the light of day. Known as the "midnight stone," kunzite has a tendency to fade when exposed to strong light or heat. These gems also have cleavage planes in two directions, so they're notoriously difficult to facet and require some extra care as ring stones.

For couples who enjoy evenings out, kunzites make excellent rare engagement ring stones.

Spessartite Garnet

Spessartite garnets (also known as spessartines) have colors ranging from fiery yellow-orange and bright orange to dark brownish red. Their colors are sometimes compared to the wings of monarch butterflies. Bright orange spessartites are known as mandarin garnets and are beautiful to behold. Spessartites with "aurora red" color, a highly saturated reddish orange hue with medium to medium-dark tone, are perhaps the most valuable variety.

California and Virginia produce spessartites, although not in great quantities. Currently, the most important sources are Nigeria and Brazil. Brazil has yielded spessartites up to 40 carats in size!

Collectors love these stones as mineral specimens, but many custom jewelers love them, too. A spessartite makes a great stone for an eye-catching engagement ring.

Benitoite

Although found in Arkansas and Japan, benitoite only occurs as gem-quality material in California.  Few people have heard of the California state gem because of its scarcity. Unfortunately, the sole gem source closed in 2005, which puts a premium on existing material.

Named after San Benito County, this gemstone typically has a deep blue color and resembles sapphire. It occurs in small sizes, generally below two carats.

Since benitoites have a Mohs hardness of 6, that means household dust can scratch them. As jewelry stones, they'll require extra care, but for couples who are Californian and proud of it, this gem may be the engagement ring stone they're looking for.

Imperial Topaz

The Ural Mountains in Russia were once the top source of imperial topaz. The Czars loved the stone so much that only the royal family was allowed to own any. Hence the name "imperial."

However, in modern times, opinions on what constitutes an imperial topaz vary. Some gem traders believe an imperial topaz must be medium reddish orange to orange-red in color. Others extend this range to include yellowish orange, orangey yellow, or yellow with reddish pleochroism. Even pink is sometimes included as an imperial color. Red topazes make up less than half a percent of all gem-quality topazes found!

Topazes require extra care as a ring stone because they have cleavage. In addition, keep them away from heat and light, which may cause them to fade. Still, it may feel good owning a store once restricted to royalty!

Cat's Eye Moonstone

A moonstone can resemble a full moon sheathed behind a cloud. This variety of feldspar scatters light, creating a soft, billowing glow. The Ancient Romans believed moonstones were solidified moonbeams, hence their name. Moonstones can come in a variety of body colors, including tan, yellow, pink, blue, and white. The glow or sheen is usually white, blue, or blue-orange.

As if this gem wasn't magical enough, some moonstones demonstrate cat's eyes, and others, rarer still, even star effects. The cat's eye is a soft, bright white band that floats on top of the body color and sheen. The layering of these different colors can create a beautiful three-dimensional effect.

Cat's eye moonstones will make enchanting rare engagement ring stones. The soft glow and ever-gliding band of light will make you want to play with this ring stone under the light.

Black Opal

Black opals are the rarest and most valuable type of opal. The vast majority (98%) comes from Lightning Ridge, Australia. With dark body color, black opals have the most vivid play-of-color of any type of precious opal.

The most desirable flash color for black opal is red, and one of the most highly desired patterns is harlequin. This pattern consists of broad diamond-shaped flashes of light set in a chessboard or quilt-like arrangement. Harlequin black opals are expensive, and black opals, in general, aren't too cheap. Nevertheless, you can still find affordable engagement ring-sized black opals.

Opals will require more care and maintenance than most other jewelry stones. However, if you treat your opal engagement ring right, you'll have a rare jewelry piece for many, many years to come.

Star Sapphire

When you have a star sapphire, you won't need to wish upon a star. These cabochon-cut stones have intersecting bands of light forming the shape of a star. Inclusions of needle-like crystals, microscopic gems trapped within the sapphire itself, create this effect. When the sapphire contains enough of these needles, they reflect light in the same way a spool of silk does. Generally, three bands of light create a six-rayed star that rolls across the stone as you turn it.

Sapphires in general have a rich body of folklore, and star sapphires have inspired their own legends and beliefs. Historically, some Christians associated the three bands of light with Faith, Hope, and Destiny and referred to this gem as the "Stone of Destiny."

Despite being much rarer than faceted sapphires, star sapphire cabochons are surprisingly more affordable. A star sapphire engagement ring would make a wonderful way of telling that special someone, "you are my star."