Diamond Napkins were made by Diamond Matches. Why, I've no idea, but they specialized in small household things. Matches. Toothpicks. They had to diversify after the match business got more competitive: Their history page notes that in 1911, "at the request of Presidenbt WIlliam H. Taft the Diamond Match Company releasd their patent of the nonpoisonous match 'for the good of mankind".

Mankind was thus duly improved.