Look no further than this guide, which will cover the meaning behind this term, and the exciting range of gemstones it includes.
Which Stones are Semi-Precious?
Before we dive into semi-precious stones, it’s important to look at the history of gemstones and how this term came to be. As early as Ancient Greece, people attempted to classify stones to find the most desirable varieties, whether to wear them as jewelry or collect them as precious objects. These designations have changed over the centuries, as tastes changed from Georgian jewelry to regency jewelry and so on. Looking into the differences between periods of jewelry design, one can see that as new gemstones were discovered, a select few were chosen as the most desirable gemstones of the time. Today, only four gemstones are referred to as precious: diamond, ruby, emerald and sapphire.
Many of the popular gemstones today, from the neon blue Paraiba tourmaline to the rainbow-hued opal, are therefore categorized as semi-precious. These intriguing gemstones possess a vast range of colors, and many have been discovered relatively recently, adding a new layer of excitement to this broad category.
Modern gemologists have moved past terms like semi-precious and precious because they erroneously imply that one category of gems is rarer or more valuable than the other, which is often false. Each gemstone has its own unique story and many different factors beyond the simple designator of precious or semi-precious play into its perceived value and rarity. Although these terms are important to know when discussing gemstones, their actual meaning has held more weight in the past than it does today.
The Value of Semi-Precious Stones
Just as gemstone classifications have changed throughout history from acient times to today, the value of semi-precious stones varies jeweler to jeweler. Even though some jewelers still divide stones between semi-precious and precious, it is important to note that many semi-precious gemstones are far more valuable than precious gems. Some of today's gemstones are also regulated in terms of quality by associations like the American Gemological Laboratories and Gemological Institute of America. Many factors affect a gemstone's value, from the quality of each individual stone, including fundamental factors like the hardness, color, clarity and cut, to its origin and the treatments the stone has undergone. The rarest gemstones across all categories have many of the same characteristics, such as vibrant, natural colors that come from the earth’s formations rather than an artificial addition. Also, place of origin becomes an important factor for many semi-precious gemstones, which often are only found in specific mines, adding layers of mystique and rarity.
Read on for an overview of some of the most impressive semi-precious gemstones from M.S. Rau’s expertly curated collection, which includes everything from estate rings to contemporary pieces.
Traditionally hailing from Brazil, Paraiba tourmaline includes copper, which gives the gemstone its neon blue color. Although other varieties of tourmaline can also be highly valuable, the Paraiba tourmaline is among the rarest semi-precious gemstones in the world. Tourmaline produces a wide variety of hues, sometimes with multiple colors within the same specimen, making it a versatile gemstone.
Most think of only one shade of blue when picturing a Paraiba tourmaline, but these rare gemstones range from neon green to dark blue colors. The most valuable Paraiba tourmalines are those with origins in Brazil, but mines in Mozambique have also produced tourmalines in this striking range.
This rare Alexandrite stone boasts two gemstone colors, appearing as rich red hue in incandescent lighting and greenish blue under daylight. The ring above shows how the same stone can appear dramatically different, creating an almost magical effect for the wearer. Named for Czar Alexander II, alexandrite can be found in Brazil and Russia, but the most desirable specimens have Russian origins. This gemstone was discovered in the early 19th century in the Ural Mountains, also the site of another incredibly rare semi-precious gemstone, the demantoid garnet. The alexandrite deposits in the Ural Mountains were very quickly depleted, making it incredibly rare to see any Russian alexandrites over a carat today. Most alexandrite specimens are now mined in Brazil and Sri Lanka.
Discovered in 1967, this exciting gemstone is named for the only country in which it is mined: Tanzania. Tanzanite ranges in hues from a light purple to deep blue, rivaling the most impressive sapphires. Experts estimate that the region where tanzanite is mined will be depleted in two decades, adding an extra level of rarity to these beautiful gemstones. Tanzanite was popularized by Tiffany & Co. and has become one of the most desirable gemstones of the day due to its rarity and stunning color. In 2002, it was added as one of the birthstones for December, making this velvety blue gemstone a thoughtful personalized gift.
Like many rare semi-precious gemstones, demantoid garnets from a specific location are incredibly rare and desirable. In this case, Russian demantoid garnets are among the rarest gemstones in the world due to their short history of mining in the Ural Mountains. Demantoid garnet is identifiable by a highly rare inclusion called a horsetail. This unique feature separates demantoids from most other gemstones, for which clarity and the lack of inclusions are highly valued. Some horsetail inclusions are so prominent that they can be seen with the naked eye. These gemstones are often compared to emeralds for their vibrant green color but have an unparalleled fire and liveliness. The garnet is also one of the most common gemstones placed in Georgian jewelry.
Red emerald is one of the best examples of how semi-precious gemstones can be far rarer than precious gemstones in some instances. Red and green emeralds are both varieties of beryl, but the red variety gets its crimson hue from manganese. Also referred to as red beryl, red emeralds are far rarer than the average green emerald as they were only mined in the Wah Wah Mountains of Utah from 1904 into the 1920s. Since then, no mine has produced gem-quality red emeralds, making this one of the scarcest gemstones in the world. Red emerald specimens are found in many important museum collections and are only occasionally large enough to be set in jewelry, making this red emerald suite even more exceptional.
If you’re intrigued by emeralds, learn more about Columbian emeralds and the beauty they can bring to any piece of rare jewelry or collection. From gemstones to precious metals, our antique jewelry identification guide can also help you determine your preferred jewelry style.
The final semi-precious gemstone highlighted in our collection is the black opal, mined in the Lighting Ridge mines of Australia. This impressive gemstone features a rainbow of hues set against a dark background, making these gemstones pop compared to white opals. Opals are highly regarded for their fantastic rainbow of colors, from bold reds to cool blues and greens. These qualities make these semi-precious gemstones a great addition to any jewelry collection.
Are you eager to start your own collection of semi-precious colored gemstones? At M.S. Rau, we seek to acquire only the rarest and most desirable specimens, meaning our collection features the top selections from every given category, including both precious and semi-precious.
Whether you plan to acquire jewelry featuring precious or semi-precious gemstones, you should learn proper jewelry care. Check out our posts on how to store fine jewelry and how to clean antique jewelry for the best tips to maintain your collection.