Diamond’s splendor has been appreciated for centuries, but there was not much scientific knowledge about it before the twentieth century. Since then, diamond knowledge has grown steadily, with …

Whether examining the laboratory-grown diamonds submitted for grading reports, growing CVD diamonds at our research facility in New Jersey, or altering these materials through treatments, GIA …

While choosing a diamond is a very personal decision, evaluating a diamond should always be a matter of precision. At GIA, we are incredibly proud that our 4Cs of diamond quality continue to educate the …

Nov 21, 2025 · Explore the GIA Guide to Diamond Engagement Ring Shapes and learn the differences between round, oval, marquise and more. Make a well-informed decision when choosing the perfect …

GIA’s Guide to Gemstones: Gem Encyclopedia GIA’s Gem Encyclopedia is a virtual journey through the science and lore of gemstones from across the globe. Each precious stone page features additional …

Fancy Color Diamond Dazzling brilliance. Captivating color. These are the planet’s most valued gems.

Mar 14, 2013 · The prospect of purchasing a diamond may seem daunting, but through GIA, an unbiased authority on diamonds, you have several handy resources to help you select the highest …

Museum The GIA Museum in Carlsbad, California introduces visitors to the vast and vibrant world of gems and jewelry. Our exhibits, spread throughout the campus, display the science and beauty of …

As the home of gemological research and education, we invented many of the instruments used by the international gem and jewelry industry, and we even created the 4Cs of diamond quality.

Presents the first scientific and historical study conducted on the 2.33 ct Winston Red, the fifth-largest known Fancy red diamond in existence.