In a jar of sauce, diamonds are the crystalline structures that develop at the bottom of the jar. Concentrate enthusiasts will be familiar with sauce carts, or vape cartridges loaded with terpene-heavy sauce. Diamonds may also refer to the crystalline structures leftover after terp sauce has been removed from the initial sauce mixture. These diamonds are usually coated in residual sauce. Diamonds can also refer to pure THCA crystals that have been isolated from refined oil.