Opal is a gemstone that ranges in color from milky white to black and can display a beautiful play of colors. It's composed of silica and water, making it one of the only gemstones that has the ability to diffuse light, giving it a unique appearance. The original Opal stone price varies based on its quality, color, and origin. On average, it ranges from $50 to $10,000 per carat. Factors like rarity, patterns, and brilliance also affect the price.