Method for forming diamond product

A method for forming a diamond product and associated diamond products, comprising polycrystalline diamond material and a composite body comprising a single crystal diamond plate with a glue that is inert to ions capable of forming radicals during electrolysis. A damage layer comprising sp2 bonded carbon is formed (S2) and the presence of the damage layer defines a first diamond layer (S1) above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer. The damage layer is electrochemically etched to separate it from the first layer. The electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 μS cm-1, (S4) and wherein the ions are capable of forming radicals during electrolysis. The etching may be completed at an elevated temperature with concentration of ion greater than 0.01M.