Intense violet-blue hues of tanzanite can rival fine sapphire at a fraction of the price – and it’s a much rarer stone! Occurring only in a small area of Tanzania, this variety of zoisite has become quite prominent. After its discovery in 1967, it quickly rose in popularity, due in part to marketing efforts by Tiffany & Co. This stone shows strong pleochroism, appearing blue, violet, or green-yellow to brown, depending on the viewing angle. Gem cutters orient these gems to feature blue or violet hues. Though almost all tanzanite undergoes heat treatment to produce its attractive blue hues, this treatment produces a stable color that makes this stone so desirable.
All rubies are rare, but those from Myanmar (formerly Burma) set the standard for quality and color. They are also exceptionally scarce. While rubies from Thailand contain relatively high iron content which can result in overly dark reds with brownish or purplish overtones, the geological conditions in Myanmar generally produce rubies with very little trace iron. As a result, these gems often achieve more vivid reds with much stronger fluorescence than their Thai counterparts. Still, a top-quality Thai ruby will rival the finest from Myanmar. With fine color nicknamed “pigeon blood,” these red gems are always in demand.
Known for the bright electric green of imperial jade, jadeite can actually occur in many colors, including lavender, yellow, orange-red, blue, black, and colorless. Highly prized in Chinese, Mayan, and Maori cultures, this stone has an extensive body of folklore. Jadeite value depends on its translucence and texture, with top-quality material appearing to be full of water, or like a drop of colored oil. Still, determining the price of a piece of jade involves more subjectivity than most gemstones. The artistry of the piece plays a very important role. There’s a Chinese saying: “Gold has value; jade is invaluable.”
Discovered in 1830 in Russia’s Ural Mountains, alexandrite has remarkable color-changing abilities. Due to trace amounts of chromium in the crystal structure, this stone appears emerald green to peacock blue in daylight but ruby red to purple under incandescent light. At the time, Imperial Russia’s colors — red and green — were in style. Thus, it’s no wonder that the Russian aristocracy coveted this stone. Named after Czar Alexander, this variety of chrysoberyl is still a rare stone. Though the discovery of alexandrite in Brazil and a few other locations has expanded this gem’s availability, it remains among the rarest stones. A modern June birthstone, alexandrite remains popular and is often synthesized for jewelry use.
The brightly saturated blue-green hues of paraíba tourmaline stunned the gem world in the 1980s. Its discovery in the Brazilian state of Paraíba spurred a rush of prospectors and miners into the area. The per carat price of these gems rose quickly and continues to grow. However, Brazil isn’t the only source of these neon stones. Similar geological conditions produced these copper-bearing gems in Mozambique and Nigeria. Still, this tourmaline variety remains among the rarest gems.
In 1981, the World Jewellery Confederation (CIBJO) declared ammolite a new organic gem. Occurring in limited deposits in the Rocky Mountains, this gem material is much rarer than diamond. Ammolite is made of the aragonite shells of marine mollusks more than 65 million years old, which display bright, iridescent colors. Any color of the rainbow, or even the entire rainbow, may appear in a single specimen. The value of these unique gems increases for rare colors, more intense iridescence and play of color, and how much the stone can be rotated with the color still visible. Today, Korite International mines most of the ammolite on the market.
At 4.2 x 2.2 cm, the ammolite in this pendant makes a statement. Watch the mesmerizing color shift as the ammolite rotates in this slide show. Adorned by diamonds and a 6 mm Akoya pearl, this pendant is a showstopper even without the matching earrings. “Garden of Giverny” © Korite International. Used with permission.
Soft, velvety, saturated blue hues characterize Kashmir sapphires. These gems contain very fine inclusions of rutile that create this soft look. The mines that once produced them high in the Himalayas ran dry in the 1930s. As a result, the price of these extremely scarce stones rises ever higher. While few will ever have the privilege of owning one of these gems, museums have many pieces on display. They’re well worth a visit.
Pearls are ubiquitous, but without the cultured pearl industry, they would be nearly non-existent. Natural pearls are extremely rare and becoming rarer every year. Due to overfishing, pollution, and ocean acidification, naturally occurring pearls appear more frequently in antique jewelry than in our planet’s oceans. Natural pearls are rarely round and often off-color. So, while the standard for matching round pearl jewelry is very high in cultured pearls, natural pearl strands will have more imperfections.
A cousin of emerald, aquamarine, and morganite, the red variety of beryl contains manganese, which imparts a bright red hue. Once called bixbite, red beryl is one of the rarest and most desirable gems. With good wearability, this gem can make an excellent jewelry stone — if you can find one! Gem-quality red beryl occurs only in Utah’s Wah Wah mountains, and most specimens are kept by mineral collectors and never faceted.
This rare stone exceeds diamond’s rarity as well as its “fire” or dispersion. Combined with its often sapphire-blue color, it’s no wonder this is a highly sought rare gem. Gem-quality benitoite occurs only in San Benito County, California (and thus a natural choice for the California state gem). When choosing a benitoite gem, consumers must decide between a dark and saturated sapphire blue with somewhat less visible dispersion or a gem with lighter tone but sparkling fire.