When equipped and activated, it offers a chance of finding uncut diamonds, uncut dragonstones, and uncut onyx gems while Mining, and also allows dragonstone and onyx to be found on a successful mining swing that yields an ore. High level rocks have a greater chance to yield these, though lower level rocks can be mined faster, nearly providing the same amount of gems per scrimshaw. The effect does not work with shooting stars, Seren stones, the lava flow mine, concentrated coal, concentrated gold, red sandstone, gem rocks, salty crablets, or alaea crablets.