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What Is a Gemstone?
A gemstone (also referred to as a gem, jewel, precious or semi-precious stone) is a mineral, rock, or organic material valued for its beauty, rarity, and durability. Typically used in jewelry, gemstones are prized for their vibrant colors, unique properties, and symbolic meanings. The durability of a gemstone is equally important, as it must be strong enough to be set in jewelry that’s worn every day. Durability is measured by the Mohs scale, which rates gemstones from 1 (the least durable) to 10 (the most durable).
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Types of Precious Gemstones
Precious gemstones, traditionally considered the most desirable and valuable, are defined by beauty, hardness, and brilliance. This category includes diamonds, sapphires, emeralds, and rubies.
Diamond
A crystal form of 99% carbon, known for its hardness at 10 on the Mohs scale and high refractive index, which gives its beloved exceptional brilliance.
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Sapphire
A variety of corundum, mostly known in blue but also found in other colors, with a hardness of 9 on the Mohs scale.
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Emerald
A green variety of beryl, colored by chromium or vanadium, and commonly included, with a hardness of 7.5–8.
Ruby
The red variety of corundum, colored by chromium, with a hardness of 9 on the Mohs scale and valued for its durability.
Types of Semi-Precious Gemstones
Semi-precious gemstones encompass a broad range of stones that offer diverse colors, patterns, and unique optical properties. Though more affordable than precious stones, many are equally beautiful and popular in jewelry designs.
Alexandrite
A chrysoberyl variety known for its color change from green in daylight to red under incandescent light.
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Amethyst
A deep, royal purple variety of quartz, with a hardness of 7 on the Mohs scale.
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Aquamarine
A blue to blue-green variety of beryl, often transparent, with a hardness of 7.5–8 on the Mohs scale.
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Citrine
A yellow to amber variety of quartz, valued for its color and affordability, with a hardness of 7 on the Mohs scale.
Garnet
A group of silicate minerals available in various colors, commonly red, with a hardness of 6.5–7.5.
Moissanite
A lab grown silicon carbide gemstone, prized for its high refractive index and sparkle, with a hardness of 9.25.
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Morganite
A pink to peach variety of beryl, colored by manganese, with a hardness of 7.5–8 on the Mohs scale.
Opal
A hydrated silica mineral known for its play-of-color effect, with a relatively low hardness of 5.5–6.5.
Pearl
A gemstone formed within mollusks, composed primarily of calcium carbonate, with a hardness of 2.5–4.5.
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Peridot
A green variety of olivine, with iron as its primary coloring agent, and a hardness of 6.5–7 on the Mohs scale.
Spinel
A mineral available in red, blue, pink, and other colors, with a hardness of 8.
Sunstone
A feldspar gemstone containing tiny metallic inclusions that produce a shimmering effect, with a hardness of 6–6.5.
Tanzanite
A blue to violet variety of zoisite, found only in Tanzania, and with a hardness of 6–7 on the Mohs scale.
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Topaz
A silicate mineral available in many colors, with a hardness of 8, valued for its clarity and brilliance.
Tourmaline
A mineral that occurs in a wide range of colors, with a hardness of 7–7.5.
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Zircon
A natural zirconium silicate gemstone with a high refractive index, available in various colors, with a hardness of 6.5–7.5.
Gemstone Color
Gemstone color, influenced by trace elements and structural formations, is one of the most critical factors in a stone’s beauty and value. The ideal color varies by gemstone; for example, deep red rubies and vibrant blue sapphires are more valuable than their lighter, less saturated counterparts.
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Gemstone Cutting and Polishing
Cutting and polishing transform rough gemstones into desirable shapes that highlight their best features. Various cuts, like round, emerald, and princess, emphasize specific aspects of each gemstone's color and clarity.
Gemstone Treatment
Treatments, including heat, irradiation, oiling, or dyeing, can enhance a gemstone’s color and clarity. Some treatments are standard practice, while others, like fracture-filling or surface coating, are disclosed due to their impact on value and durability. Please note that Brilliant Earth only offers industry-accepted treatments, such as heat and irradiation.
Gemstone Grading
Gemstones are graded based on their color, clarity, cut, and carat weight. Different systems, such as those developed by the Gemological Institute of America (GIA), provide standards that help buyers understand the quality of their chosen gemstone.
Gemstone Value
The value of gemstones depends on factors like rarity, color, clarity, cut, carat weight, and whether a gemstone is natural, or lab grown, treated or untreated. Precious stones like diamonds, rubies, sapphires, and emeralds typically hold the highest value, but rare semi-precious stones, such as imperial topaz and tanzanite, can also be expensive.
How to Choose a Gemstone
Here are several factors to consider when selecting a gemstone for your jewelry:
Color
Gemstone color is typically assessed based on three qualities—hue, tone, and saturation. Hue refers to the gemstone's main color, while tone is how light or dark the color appears. Saturation measures the intensity or vividness of the color. Look for gemstones with a color that appeals to you personally, keeping in mind that richer tones with even saturation are often considered more valuable.
Clarity
Clarity refers to the visibility of inclusions (internal features). While clarity is a key factor in evaluating a gemstone's appearance, some gemstones, like emeralds, are commonly found with inclusions. In other gems, such as aquamarine, high clarity is more common and expected. Choose a clarity level that aligns with your preferences, bearing in mind that inclusions can sometimes add uniqueness to a stone.
Cut
The cut of a gemstone impacts its overall brilliance and shape. A high-quality cut maximizes light reflection and enhances the gem’s beauty. Choose a cut that not only complements your jewelry style but also brings out the stone’s natural luster and color.
Carat Weight
Gemstone size is measured in millimeters. Decide on a size that fits your budget and style, keeping in mind that larger carat sizes may show inclusions more visibly.
Durability
A gemstone’s durability is determined by its hardness, toughness, and stability. Hardness refers to resistance to scratching, while toughness is resistance to breaking or chipping. Stability indicates how well the gem withstands heat, light, and chemicals. For daily wear, choose a durable stone like sapphire or diamond, whereas softer stones like opal or pearl are better suited for occasional wear.
Personal Style and Budget
Finally, choose a gemstone that fits your personal style and budget. Gemstones vary widely in cost depending on factors like rarity, quality, and origin. While traditional stones like diamonds and sapphires are popular, exploring semi-precious gemstones can offer unique colors and styles at a more accessible price.
