THC diamonds aka THC crystalline look exactly like the little gems they are so fondly named after and are 99% pure THC-A. THC-A is an inactivated cannabinoid. THC-A will convert into THC after it has been heated to extreme temperatures but is utterly ineffective on its own and will not produce the same psychoactive and euphoric sensations you would expect from a product high in THC.
Since THC diamonds only contain THCA adding them to a drink or an edible isn’t going to give you the effects you are seeking. The best way to use THC diamonds is to either smoke, vape or dab them; any method that utilizes a heating element that will reach 350 Fahrenheit or higher should be sufficient to release and activate the THC within.