Minerals have been classified since ancient times. In the 1800s, terms like “precious” and “semi-precious” were introduced to distinguish between gemstones.
While today’s understanding of gemstones is more detailed, these traditional terms still affect the pricing of jewelry. Learn about the differences between these broad groups of gemstones.
What Are Precious Gemstones?
“Precious” describes a select group of gemstones that are rarer in nature and have a vibrant yet still translucent appearance. These include diamonds, rubies, emeralds and sapphires. On occasion, jade, opals and pearls are included but still considered semi-precious.
A handful of key characteristics define precious stones:
- Hardness: Although this varies among the nearly scratch-resistant diamond and the softer, more delicate emerald, precious stones are harder and less likely to crack than semi-precious ones. Using the Mohs scale, precious stones fall within the 10 to 7.5 range.
- Visuals: Excluding colorless diamonds, precious stones are transparent yet often display visually rich colors. Meanwhile, many semi-precious stones like turquoise don’t allow light to pass through, even when cut.
- The 4Cs: Although the 4Cs are often associated with diamonds, the same factors are used to evaluate precious gemstones. As such, rubies, emeralds and sapphires with no inclusions are extremely rare and significantly increase price.
- Location: Although certain semi-precious stones are considered rare – like tanzanite – precious stones can be found in select locations throughout the world in small quantities. Within each group, certain colors and varieties may be harder to come by.
What Is a Semi-Precious Gemstone?
Gemstones that do not fall within the selective “precious” category are classified as semi-precious, although more share similar chemical characteristics. Common stones used for jewelry include beryl, pearls, alexandrite, agate, amethyst, aquamarine, garnet, lapis lazuli, moonstone, opal, peridot, rose quartz, spinel, tanzanite, tourmaline, turquoise, topaz, citrine and zircon.
In terms of visual appearance, rarity and jewelry making, semi-precious stones are more widely available and tend to be priced lower. Yet based on inclusions and rarity, certain semi-precious stones may be priced higher. Examples include tanzanite, demantoid and tsavorite garnets, spinel, natural pearls and moonstone.
Certain qualities tie together this vast group of gemstones:
- Color Variety: Due to numbers and variations, semi-precious stones cover a broad spectrum of colors, from shade to intensity. These shades are often lighter than what you’ll find from most precious stones.
- Softer Composition: Semi-precious stones tend to be rated a 7.5 or less on the Mohs hardness scale, increasing the likelihood they may chip.
- Abundance: Although there are exceptions, semi-precious stones are found in more locations throughout the world, often in larger quantities.
The International Colored Gemstone Association breaks down semi-precious gemstones based on rarity:
- New Classics: Harder-to-find stones like tanzanite, tourmaline, imperial topaz, aquamarine and tsavorite garnet.
- Collector: The next level down applying to spinel, moonstone, zircon and beryl.
- Affordable: More abundant gemstones like amethyst, blue topaz, citrine, rhodolite garnet and peridot.
Whether you’re shopping for an engagement ring or fashion jewelry, keep these points in mind as you browse our selection of precious and semi-precious gemstones. To explore your options, visit one of our Connecticut stores today.
