I passed by this rock and thought there has to be a cache here so people will look at rocks more 
Please note that Rangitoto doesn't offer any shops and it will get quite hot here. Bring enough water and food with you. Also take everything back to the mainland again. Don't throw garbage or anything away on Rangitoto. We want this island to remain as beautiful as it is. And if you see rubbish anywhere just pick it up and make the island a nicer place!