Mangosteen is called a superfruit, because it is rich in fibers, antioxidants, nutrients like Vitamin C, B1, B3, B9, and minerals such as copper, manganese, and magnesium. Mangosteen can become rock hard which is often caused by cold storage. Don't store mangosteen in the fridge if you want to keep it soft. You can make a healthy tea from the rind of the mangosteen. Peel the outer layer from the mangosteen or scoop out the red inner layer with a spoon, divide it into smaller parts and dry it in the sun. You can use these dried parts to make your tea using hot water. Add honey for a sweeter taste. Cheers!