Divine crystals are items that can be found while training Divination during The Bird and the Beastworld event. They can be released at a faction's tower for faction score and renown. They provide 750 renown each, or 1,500 renown each with PvP mode turned on. Only one divine crystal can be obtained at a time.
To not receive any divine crystals, open the Adventures interface, click "The Bird and the Beast" tab and then uncheck "Gather divine crystals" in the top right corner.
The crystals do not need to be obtained while doing divination at friendly convoys: they can be collected at any energy rift across Gielinor. Players may obtain more than one in their inventory, however only one will be counted toward gaining renown. Multiple divine crystals can be turned in daily, but they must be turned in individually. If a crystal is turned in while another is in the bank, both will disappear and will only give renown for the one turned in. This may be a glitch.
The crystals will not give any renown if the player turns them in after reaching their daily contribution limit. They are bankable, so they can be saved for the next day.