Just this minute I saw a brief Macy's TV commercial for a very cheap "diffused sapphire" ring and something pink as well. (Didn't catch it. Did anyone else see it?) Whatever, are they admitting diffusion or bragging about it?
They will succeed in numbing the ears of the people, making them comfortable with the term without telling them what it means or the effect of it. Meanwhile they will apply to uspto for Diffuse Light® , the best light for Sapphires of a Certain Color or some such linguistic bile so that they can eventually talk about diffuse light and claim that as disclosure.