What stones are similar to opal?

Stones similar to opal include labradorite, which exhibits a play of color known as schiller, and moonstone, known for its adularescence and shimmering effect. Other alternatives are fire opal, which displays vibrant colors, and boulder opal, featuring the host rock integrated with the opal. Additionally, synthetic opals, created in labs, mimic the appearance of natural opals but are more uniform in color.