Since THC diamonds only contain THCA adding them to a drink or and edible likely 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. Basically, any method that utilizes a heating element that will reach 350 Fahrenheit or higher should be sufficient to release and activate the THC within.
Whether you add these crystals to your bowl or pipe or add it to joints, the result is a potent THC experience. If you want more flavor and terpenes, you can add Terp Sauce or add Terpenes in one of several available options. Consider buying THC Diamonds in terp sauce if you can’t go without those terpenes. 

While you can enjoy these THC rocks in a variety of ways, they can unfortunately not be eaten as an edible.
Whatever you decide, ensure you manage the dosage carefully. This is an extremely potent product, so start low and go slow lest you green out!