Opal is a reflective mineral in Stardew Valley that you need in order to complete the Artifact Collection in the Museum. The challenge, however, lies in acquiring this sedimentary stone, as it cannot be bought from vendors, and its drops involve intricate RNG. Nevertheless, this guide unveils the quickest method to amass Opals, offering insights on cultivating them on your own farm. Here’s everything you need to know about the rainbow-light-reflecting gemstones in Pelican Town.