Gemstones are valued based on the Four Cs - color, clarity, cut, and carat. Precious stones include diamonds, sapphires, ...

Silicates—including quartz, mica, olivine, and precious minerals such ... trace elements can produce other colors, allowing beryl to form semiprecious stones such as aquamarine.

semi precious gemstones ... As with other colored gemstones, color is one of the most important factors determining the price of your ruby. The most valuable of rubies tend to be an intense ...