The macadamia tree is a hardy tree. It doesn’t start to produce economic quantities of nuts until it is 8 years old. The tree lives up to 70 years and can reach a height of 60 feet. There are about 10 species of macadamia, but only two of these species have edible nuts.
The fruit which contains the nut is in a very hard shell. The shell is green when immature and then turns brown when mature. The outside skin becomes hard and woody. The fruit can contain one or two nuts. The nuts are about the size of a marble. The seeds must be dried which enables the seed to shrink from the hard outside skin. Once the seed shrinks from the outside, then the hard shell can be cracked to release the seed. New varieties have been developed which have softer shells which has helped to lower the price.