The gemstone emerald is characterized by its striking green color, which can vary in shade from light to deep green. This color is primarily due to the presence of chromium and sometimes vanadium in the beryllium aluminum silicate mineral known as beryl. High-quality emeralds are often highly valued in the gemstone market and are considered one of the four precious gemstones, along with diamonds, rubies, and sapphires. Their vivid green hue makes emeralds particularly sought after for fine jewelry.