Diamonds
Gemstones
Pearls
Metals
FAQs
Gemstones come in a virtual rainbow of colors, from pale yellow to crimson red. Some present a subtle hint of color, while others are entirely saturated with a deep rich hue. Throughout history, gemstones have been used to symbolize numerous things, from social status to important milestones. Many gemstones are identified as birthstones, others are considered a sign of wealth or nobility, while some gemstones are thought to bring happiness or protection. Today, most of us wear gemstones because we simply enjoy their beauty. So, whether you prefer to wrap your wrist in luxurious amethysts or adorn your hand with a sapphire engagement ring, you’ll love the way a high-quality gemstone makes you look and feel.
Colored gemstones are checked for consistent color, matching stones and minimal inclusions. All Costco Gemologists have graduated from a program with the Gemological Institute of America (“GIA”).
The value of a gemstone is determined by the overall evaluation of four key characteristics: color, clarity, cut, and size. There are other factors that may also affect a gemstone's value, including supply and demand, degree of treatments, and the rarity of the stone.
Color
Color is the most important characteristic of any gemstone. For many people, color comes down to personal taste. On a professional level, a gemstone’s color is judged on its overall consistency, its richness and depth, and of course, its brilliance. For most gemstones, a color that is medium in tone, not too dark or too faint, is the most desired.
Cut
Each gemstone is unique, and should be cut in a way that best showcases its positive attributes. Many gemstones are cut simply for size, with little concern for other characteristics. But a talented gemcutter will choose a cut that strikes the perfect balance between color, clarity and brilliance. A well-cut gemstone should be even in color, have proportioned facets, and a smooth lustrous surface. There are five possible ratings for cut: poor, fair, good, very good, and excellent.
Clarity
Nearly all gemstones have internal flaws called inclusions, which are tiny pieces of material found within the stone. These inclusions can range from minor to severe, and can affect the look and strength of the stone. They are the key characteristic in determining the clarity of a gemstone. The fewer inclusions, the better the clarity.
Size
Because gemstones vary greatly in density, the standard practice of measuring weight in carats does not always give an accurate description of a gem's true size. More commonly, a gemstone's size is derived by measuring its length and width, or diameter, in millimeters. In some cases, a gemstone’s size will be listed in both millimeters and general carat weight.
In the jewellery world, there are three gemstones thought to be the most coveted: rubies, emeralds, and sapphires. These gemstones, referred to as “The Big 3”, have been the most renowned and sought-after for centuries. Today, they continue to be among the most valued gemstones, and due to their rarity and continued popularity, some of the most expensive.
Although The Big 3 are undoubtedly gorgeous gemstones, there are also many more stunning and highly valued gemstones on the market, each with their own unique characteristics and beauty. At Costco, we strive to offer our members a diverse selection of quality gemstone jewellery, so that you can choose the one that appeals to you most.
Ruby
The regal and much sought-after ruby is prized for its vibrant pink-red hue and incredible luster. Its color is considered by many to be the perfect reflection of romance and passion. It is the rarest and most expensive variation of the mineral corundum. A high-quality ruby is considered to be one of the most valuable gemstones, and can often be more expensive than a diamond of similar size and quality. A natural ruby is incredibly strong and durable, making it a wonderful choice for jewellery.
Lab Created Emerald
The rare and glamorous emerald, is a rich deep green that often has a hint of blue. It is a green variation of the mineral beryl, and it is one of the most coveted and expensive gemstones on the market. An emerald is thought to symbolize balance, harmony, and romantic happiness. It is a strong gemstone that does not scratch easily, ensuring that it will wear well. Emeralds are often set in a yellow gold, which is thought to be a warm backdrop for the radiant green of the stone.
Sapphire
The elegant and sophisticated sapphire is a variation of the mineral corundum, and it is highly regarded for its strength, durability, and brilliance. Natural sapphires come in a virtual rainbow of colors, with the most valuable being blue, pink, and orange. Sapphires are thought to symbolize wisdom, fidelity and good fortune, which is why they are a popular choice for wedding jewellery.
Most colored gemstones on the market today, have had some degree of treatment during the production process.The most common treatment or enhancement is heating, which is done to intensify color and improve overall appearance. Unless otherwise stated, all colored Gemstones offered by Costco have been treated during the production process.
Lab-created emeralds are the only synthetic gemstone carried by Costco. Natural emeralds are incredibly rare and therefore, extremely expensive. That’s why the majority of emeralds found in the marketplace are lab-created emeralds. Due to the skill and expense involved in production, emeralds are among the most expensive lab-created gemstones available. Unless otherwise stated, all emeralds offered by Costco are lab-created.
Gemstones vary in hardness and are susceptible to becoming scratched, that’s why it’s important to wear and store your gemstone jewellery with care. Extended exposure to direct sunlight, extreme heat, or sudden temperature changes may cause gemstones to fade or break. Avoid all harsh chemicals such as bleach, ammonia, chlorine, hair spray, and perfume, as they may cause permanent damage to metal and gemstones. Do not wear your gemstone jewellery while using a pool or hot tub.
Most gemstone jewellery can be gently cleaned with warm water, a small amount of mild soap, and a soft-bristle brush or cotton cloth. Rinse the jewellery thoroughly, and ensure that it is completely dry before storing or wearing. Commercial jewellery cleaners are generally safe to use on most gemstone jewellery; however, some solutions do contain chemicals that can cause permanent damage to sensitive gemstones. Use with caution.
