Unique Opal Jewelry come in different sizes and shapes. The color varies from pale, milky white with fragile internal shades of pale blue and primrose yellow through milky white with delicate inner colors of dull view and primrose yellow to vivid blue, green, and black that flash red, gold, and green fire. Real Opal evolved as an amalgamation of water and silicon – dioxide. Over a lengthy period, water flowing from the ground picks up silica from sandstone and cleans it into crevices and cracks in the rock. Post it, the moisture slowly evaporates, leaving a deposit of silica, and as the cycle repeats, the Opal gradually starts evolving.