Ten Rare and Expensive Engagement Ring Stones


Summary
Although rare doesn’t necessarily equal expensive in the gem world, these ten rare gemstones do command high prices. All of these stones are visually spectacular, perfect for engagement rings. So, if money is no object, take a look at these expensive engagement ring stones and find one as rare as your love for your partner.
Reading time: 13 min 18 sec
demantoid and diamond ring - rare and expensive engagement ring stones
Three-stone ring, cushion-cut demantoid and baguette-cut diamonds. Photo courtesy of liveauctioneers.com and Fellows.

Before You Buy an Expensive Engagement Ring Stone

Most of the gems on this list have a Mohs hardness equal to or greater than 7. That’s a good indicator that a stone is suitable for the rigors of daily ring wear. Mohs hardness measures a material’s resistance to scratching. Household dust actually has a hardness of 7, equal to that of quartz, so most of these gems will easily resist scratches due to this common hazard.

However, a high hardness, even diamond’s famous 10, doesn’t make a gem indestructible. Most gems, even diamonds, can shatter when struck. Tenacity is a measure of how well a material resists physical blows. All the gems on this list, except jadeite, have a “brittle” tenacity. (Jadeite has an unusually tough tenacity for a gem). Although protective settings are frequently associated with softer, more delicate gem materials like opals, you might consider such a setting for your engagement ring. Protective settings can also help prevent your expensive gemstone from snagging on clothing and possibly coming loose.

Although the stone appears to be floating, this tension setting actually protects and holds the stone securely while showing off its brilliance. © James Allen. Used with permission.

Many of the gems on this list are durable enough to be cleaned mechanically with a steam or ultrasonic system. However, some have inclusions or heat sensitivity and should only be cleaned at home with a soft brush, mild detergent, and warm water. Taking any of these gems to a professional jeweler for cleaning may be a wise choice.

Find out if your homeowner’s insurance covers jewelry as well as any limits. You may want to purchase additional gem and jewelry insurance.

Finally, if you’re having second thoughts … about the prices, take a look at these rare but inexpensive gem options.

1. Alexandrites

Emerald by day, ruby by night,” alexandrites change from green or blueish green under daylight to red or purplish red under incandescent light. Discovered in the 1830s in Russia, this unusual color change stone immediately became a favorite of the Czars. (Red and green reflected the Imperial military colors).

6 mm lab-created alexandrite in a 14k nature-inspired yellow gold bypass setting, with a diamond halo and tanzanite accent gems on the shoulders. © CustomMade. Used with permission.

Alexandrites have a very high hardness (8.5), so they resist scratching very well, and make wonderful ring stones. However, in this case, rarity and demand make alexandrite one of the most expensive gems in the world. Even lab-created alexandrites are quite expensive. 

You can learn more about buying alexandrites here.

5 mm alexandrite ring - expensive engagement ring stones
5 mm lab-created alexandrite in a 14k white gold flower setting, with white opal and black diamond accents. © CustomMade. Used with permission.

2. Paraíba Tourmalines

Tourmalines come in every imaginable color and sometimes even show multiple zones of different colors. Most varieties are relatively inexpensive, but in 1989, the discovery of electric neon-blue to blue-green tourmalines in Paraíba, Brazil took the gem world by storm. Demand and prices for these rare paraíba tourmalines grew rapidly and continues unabated.

paraiba tourmaline - rare and expensive engagement ring stones
An oval paraíba tourmaline, highly included but with beautiful color. © Urth Kandi Jewelry. Used with permission.

Since the initial discovery, tourmalines with similar colors have been found in Nigeria and Mozambique. Most major gemology labs describe these as paraíba tourmalines, too, since they all belong to the same tourmaline species, elbaite, and get their color from their copper content. Nevertheless, these gems are still rare, and those from Brazil sell at higher prices.

In addition to a hardness of 7-7.5, paraíba tourmalines have no cleavage. This means they are less likely to split, so they can better resist damage from blows.

You can learn more about buying paraíba tourmalines here.

paraiba tourmaline and diamond ring - rare and expensive engagement ring stones
Paraíba tourmaline and diamond ring, 14.16-ct cushion-cut center stone and 2.92-ctw diamonds mounted in 18k gold. Photo courtesy of liveauctioneers.com and Joshua Kodner.

3. Cat’s Eye Chrysoberyls

While many gemstones can show chatoyancy, a “cat’s eye” effect, cat’s eye chrysoberyls are the most valuable. However, not all chrysoberyls show cat’s eyes. In fact, alexandrites are a variety of chrysoberyl, and they very rarely display chatoyancy. Cat’s eye chrysoberyls usually have yellowish green, greenish yellow, or yellow body color. The most prized stones have a sharp “pupil” and demonstrate a neat “milk-and-honey” effect when held obliquely to a strong light — one side shows a “honey” body color, the other has a milky appearance.

cat's eye chrysoberyl - expensive engagement ring stones
Cat’s eye chrysoberyl, on display at the San Diego Natural History Museum, California, USA. Photo by Stickpen. Public Domain.

Lapidaries usually cut cat’s eye chrysoberyls into cabochons to maximize the cat’s eye effect. With a hardness of 8.5, indistinct cleavage, and high luster, they make durable, luscious, glowing gemstones. Although traditionally used for men’s rings, they can be incorporated into any type of jewelry, including delicately styled engagement rings.

cat's eye chrysoberyl ring - expensive engagement ring stones
18k white gold cat’s eye ring, with one pavé diamond. Photo courtesy of liveauctioneers.com and Wealthier Art & Auction.

4. Colored Diamonds

Although white or colorless diamonds are the most popular and romanticized expensive engagement ring stones, they’re not rare. However, natural colored diamonds are incredibly rare, with only one occuring in 10,000 natural diamonds. If you want a truly jaw-dropping rarity with the fame, hardness, and dispersion or “fire” of diamonds, consider one of the following colored diamonds.

Pink Diamonds

Natural pink diamonds are quite rare, yet most people have heard of them because of celebrities like Mariah Carey and Jennifer Lopez, who have received pink diamond engagement rings. The Argyle mine in Australia is known for producing pink diamonds. It takes 1 million carats of rough from the Argyle mine to yield a good quality 1-carat pink diamond!

The Pink Star, formerly known as the Steinmetz Pink, is the largest pink diamond to receive a Vivid Pink color grade by the GIA. At a whopping 59.60 carats, this diamond is valued around $25 million.

Pink Star diamond - expensive engagement ring stones
The 59.60-ct Pink Star diamond. Photo by Diamondhistorygirl. Licensed under CC By-SA 4.0.

Blue Diamonds

Natural blue diamonds are also well-known but very rare. They tend to have light, grayish blue colors but are still quite stunning. Blue diamonds tend to cost tens of thousands per carat in lighter tones and hundreds of thousands per carat in darker tones. The deep grayish blue 45.52-ct Hope Diamond is one of the most famous gems in the world. Jennifer Lopez also received a blue diamond ring from an ex-husband.

blue diamond - expensive engagement ring stones
Radiant-cut blue diamond, 0.17 cts, VS2. © James Allen. Used with permission.

Green Diamonds

Natural green diamonds can easily start at tens of thousands per carat. The 40.70-ct Dresden Green, the largest and most famous green diamond, is probably priceless due to its interesting provenance.

green diamond - expensive engagement ring stones
Radiant-cut green diamond, 2.13 cts, VVS2. © James Allen. Used with permission.

Red Diamonds

The rarest and most expensive of all diamonds, red diamonds cost at least hundreds of thousands per carat. The largest red diamond in the world, the internally flawless (IF), 5.11-ct  Moussaieff Red, cost $1.32 million per carat. That also makes it the most expensive diamond in the world!

To learn more about buying colored diamonds, check out our guides for pink diamonds and blue diamonds.

5. “Jedi” Spinels

First discovered in Myanmar in 2001, these neon hot pink spinels received the Star Wars-inspired nickname “Jedi” because they’re free of the “Dark Side.” This refers to their lack of dark tones, which can lower the value of spinels. The neon glow of “Jedi” spinels comes from their strong fluorescence. In other spinels, a high iron content inhibits this glow. 

While most natural spinels are very durable and fairly rare, they’re also relatively unknown to many gem buyers. This usually keeps their prices down. “Jedi” spinels are very rare, but interest in them is growing. This will drive up demand and prices. Be aware that vendors may try to market their spinels as “Jedi.” However, unless they exhibit that neon hot pink color, they don’t merit that designation.

“Jedi” spinels from the Man Sin mine (Mogok, Myanmar), on a broker’s hand in the Umbrella Market and on gem dealer Jeffery Bergman’s fingers. Photos by Jeffery Bergman, © Primagem. Used with permission.

You can learn more about buying spinels here.

6. Jadeites

The gem material known as jade can be one of two distinct minerals: jadeite or nephrite. Of the two, jadeite is much rarer and more expensive. Jadeite can occur in many colors, including white, orange, yellow, gray, black, and lavender. However, deep “Imperial” green is the most highly valued color of jade and only occurs in jadeite. When paired with translucence, such pieces are greatly prized. When polished to a high luster, jadeites will look amazing.

jadeite ring - expensive engagement ring stones
Imperial green jadeite and diamond ring, 18k white gold setting. Photo by Sarah J Y Wong. Licensed under CC By-SA 4.0.

With a hardness range of 6.5 to 7, jadeite can have a hardness below that of household dust. This means some pieces may have an increased vulnerability to scratching. However, jadeite is also one of the toughest gem materials available. Jadeite has very high tenacity and no cleavage. This means it has great resistance to chipping and cracking. 

Lapidaries will usually cut jadeites into cabochons for ring settings, but they can also make distinctive hololith rings, carved from a single piece of stone. Such an unusual ring with jadeite’s gemmy texture will surely catch the eye!

jadeite hololith ring and cabochon - expensive engagement ring stones
Jadeite ring and cabochon. Photo courtesy of liveauctioneers.com and Gianguan Auctions.

Jadeite’s toughness has inspired folkloric beliefs that it has protective properties, especially among the Chinese. Indeed, the “Jewel of Heaven” enjoys a strong consumer market in China and has even fetched the highest recorded price per carat of any gemstone. A green jadeite necklace sold for $9.3 million in auction at Christie’s in 1997.

You can learn more about buying jade — both jadeite and nephrite — here.

7. Rubellites

Rubellite is the trade name for purplish, orangey, or brownish red tourmalines that approach the color and saturation of rubies. Although rarer than rubies, rubellites are less expensive. In fact, they’re the most affordable gemstones on this list. Nevertheless, rubellite has had some notable devotees. In the 1880s, much of the rubellite mined in California was shipped to China to satisfy the Empress Dowager Cixi’s passion for this stone.

rubellite - expensive engagement ring stones
Purplish red pear-shaped rubellite. © Urth Kandi Jewelry. Used with permission.

For an expensive engagement ring stone, rubellite can offer couples a variety of options. It comes in a wide range of beautiful reds: mauve, magenta, rose, pale pink, and blood red. Lapidaries can also cut these stones into beautiful faceted gems as well as cabs. Some cabs may even show a “cat’s eye” effect, due to tubular inclusions within the stone.

Although rubellites are durable gems, they often do contain inclusions. For this reason, don’t clean them with mechanical systems. Instead, use a soft brush, mild detergent, and warm water at home or else take them to a professional jeweler.

You can learn more about buying rubellites here.

rubellite ring - expensive engagement ring stones
14k white gold rubellite and diamond ring, center stone 1.5 cts, diamonds 0.75 ctw. Photo courtesy of liveauctioneers.com and US Jewelry Liquidations.

8. Demantoid Garnets

Although many varieties of garnet are abundant and affordable, demantoids are extremely rare and very expensive. These stones come in green colors that rival emeralds but are far livelier. First discovered in Russia in the early 19th century, demantoids commanded the love and attention of the Czars and aristocracy. Carl Fabergé frequently used them in his creations. Not only do the finest demantoids have an intense green color, they also exceed the dispersion of diamonds and the brilliance (light return) of many gems, including rubies and sapphires.

While inclusions visible to the naked eye usually reduce the value of most gems, a demantoid’s distinctive yellow “horsetail” inclusions of radiating fibers can increase its value and add even more visual appeal.

trilliant-cut demantoid garnet - expensive engagement ring stones
Modified trilliant brilliant-cut demantoid, 2.47 cts, 8.0 x 8.0 x 5.0 mm, Antetezambato, Ambanja District, Antsiranana Province, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

Demantoids rarely occur in sizes larger than three carats. Because of their beauty and rarity, prices for demantoids can also rival those of emeralds. The hardness of demantoids can range from 6.5 to 7, so some stones may have increased susceptibility to scratching. Garnets may have some heat sensitivity, so clean demantoids only with warm water, detergent, and a soft brush

You can learn more about buying demantoids here.

9. Color Change/Blue Garnets

It was commonly thought that garnets existed in all colors except blue, until blue garnets were discovered in Madagascar in 1998. Incredibly rare gems, they usually appear blue to greenish blue in sunlight and purplish pink in incandescent light. Their color change can be even more pronounced than that of alexandrite.

This color change garnet from Africa goes from blue to purple. © All That Glitters. Used with permission.

Because of their color change and rarity, blue garnets can fetch up to $1.5 million per carat! They’re now known to occur in the United States, Russia, and Turkey as well. The most expensive blue garnet was a 4.2-ct beauty that sold for $6.8 million in 2003.

The hardness of some garnets can range from 6.5 to 7.5, so some may have increased susceptibility to scratching. They may also have some heat sensitivity, so clean color change/blue garnets only with warm water, detergent, and a soft brush

You can learn more about buying garnets in general here and more about garnets as engagement ring stones here.

blue garnet crystal - expensive engagement ring stones
A blue-violet garnet crystal from Madagascar, 0.8 x 0.8 x 0.8 cm. © Rob Lavinsky, www.iRocks.com. Used with permission.

10. Red Beryls

Related to aquamarines and emeralds, red beryls are the red variety of the beryl gem species. Gem-quality crystals occur only in the Wah Wah Mountains of Utah. Red beryl is so rare that it’s estimated there’s only one gem-quality red beryl crystal for every 150,000 gem-quality diamonds! Sizes over one carat are even rarer.

emerald-cut red beryl - expensive engagement ring stones
Natural emerald-cut red beryl, 7.50 cts. Photo courtesy of liveauctioneers.com and Jasper52.

Red beryl can fetch up to $10,000 per carat. If you’re buying a red beryl, make sure it comes with an official certificate and it’s not a simulated or imitation stone.

Due to inclusions, never clean this gem with a steam or ultrasonic system. Either use a soft brush, mild detergent, and warm water at home or take it to a professional jeweler.

red beryl ring - expensive engagement ring stones
14k gold ring with red beryl and diamonds. Photo courtesy of liveauctioneers.com and Henry’s Auktionshaus AG.

A Note on Natural Pearls

Although cultured, farm-raised pearls are readily available at affordable prices, natural pearls — formed in the wild — are exceedingly rare and can be incredibly expensive. To learn more about pearls, consult our pearl buying guide and our pearl engagement ring guide. Pearls also require significant extra care for cleaning, storing, and wearing, more so than any gem on this list.

About the author
Phoebe Shang, GG
A gem lover and writer, Phoebe holds a graduate gemologist degree from the Gemological Institute of America and masters in writing from Columbia University. She got her start in gemology translating and editing Colored Stone and Mineral Highlights for a professor based in Shanghai. Whether in LA, Taipei, or New York, Phoebe spends her time searching for gems to design and being lost in good books.
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