Which of the following is classified as a gem treatment?

Fracture filling is considered a gem treatment because it involves the process of filling inclusions or fractures within a gemstone with a substance, typically a glass or resin, to enhance the clarity and overall appearance of the stone. This treatment can effectively reduce the visibility of internal flaws, which can significantly improve the stone's market value and aesthetic appeal.

While laser drilling, heat enhancement, and dyeing are also recognized as gem treatments, fracture filling specifically focuses on addressing and improving clarity by modifying the internal structure of the gemstone. Each of these treatments serves to enhance the gem's visual characteristics, but fracture filling stands out as a method that directly alters how light interacts with the gemstone by filling in imperfections.