"Material cu layered in 24k gold" means that the material is copper (cu) that has been coated with a thin layer of 24-karat gold. This can be done through various methods such as electroplating, which involves passing an electric current through a solution containing gold ions to deposit a layer of gold onto the copper surface. The "24k" refers to the purity of the gold used, which is the highest fineness available and contains 99.9% gold. This layering process allows for a decorative and valuable finish while retaining the properties of the underlying copper material.