Precious Opal presents a “play of colour” along its surface. This “play of colour” determines whether an opal is precious or common. Flashing with iridescent colours when viewed from different angles, when the light source moves, or the stone itself moves. These flashes are known as the opals “play of colour” and can come in a multitude of colours, such as indigo, purple, blue and green, from lower wavelengths of light passing through the stone. To yellow, orange and red from the higher wavelengths passing through. The “Play of colour” opals have is what makes them a popular and unique gemstone. With the higher wavelengths being of considerable value.