Precious Stone Pencil is specifically designed for cleaning precious stones (diamonds, sapphires and rubies). Article by Hagerty.

Item specifically designed for the thorough and deep cleaning of jewels and diamonds, sapphires and rubies. The formula of this gel contains specific polishing and cleaning agents that restore shine, and the soft bristles of the brush reach the most hidden parts of the stones and the frame. Easy to use and ideally sized for traveling too. Instructions for use: 1. Rotate the upper part of the pencil until the gel reaches the bristles; 2. Gently brush the stones; 3. Rinse and dry.