In most gemstone grading reports, ... While richer and deeper hues are typically better for gemstones, if a ruby is too dark in color, it may actually negatively affect the price.

Israeli tech lets diamonds’ true colors, and clarity, shine through Machines can take over from gemologists in grading 2 of the gems’ famous 4 C’s, says Sarine Technologies ...

The lack of a grading system for the popular stone has prompted a father-son team to ... is as distinctive as the people who love it and is unrivaled among other gems for its history and color.

Garnet does have other color varieties, including orange, green, purple, blue and yellow. A garnet's color depends on its chemical composition, according tothe International Gem Society.