Buttery-rich macadamia nuts have a pleasurable melt-in-your-mouth consistency. Native to Australia, macadamia trees have been planted in Hawaii, where they flourish. Because the shells are very hard, the nuts are usually sold shelled in vacuum-packed jars or in bulk. Shelled nuts go rancid quickly and therefore should be used immediately or stored in the refrigerator. The delicious oil extracted from macadamias is extremely low in saturated fats, free of cholesterol and high in omega-3 fatty acids, making it healthier than olive oil. The oil should also be refrigerated.