Easter Island (also called Rapa Nui) is a special territory of Chile. It is located in the southeastern Pacific Ocean and is made up entirely of volcanic rocks. Easter Island rocks have been used to make massive sculptures called Moai, for which the island is most well known and are an exquisite example of the use of volcanic rocks in sculpture.

The rocks that were used to create the sculptures are of a particular type called tuff and have specific chemical compositions. They were deposited in sea water by the volcanic eruptions that formed them. These rocks’ individual characteristics vary but all are highly porous and are able to be easily worked when producing the Moai sculptures. This is as a result of their low density and is the main factor that allowed such large rocks to be used to create the statues.

The other types of volcanic rocks on the island were unsuitable for many reasons including that they were too heavy (basaltic lavas), too fragile (obsidian) or were too loose (scoria cones).

In fact the Easter Island rocks that were used to form the Moai statues have been identified as coming from a specific area called the Rano Raraku tuff. Studies show that the rocks from this area were used to create a large number of the statues. The rocks consist mainly of hyalotuff which results when volcanic glass is modified when it comes into contact with seawater.

The Rapa Nui people had a stone age culture and used the local stone extensively. The large stone statues of Moai (of which there are over 800 examples) were carved approximately 500 to 1000 years ago. Although there is much speculation, no definitive answer to the question ‘Why were they created?’ has been found though some have posited ancestor worship and representations of aliens as possibilities.

The native islanders that created them used stone hand chisels made from basalt remnants of which can be found at the site of the Rano Raraku quarry. The chisels were sharpened by breaking off the ends to create a new edge. The stone from which the statues were formed was also regularly wetted with seawater to make it easier to work. It is estimated that while many teams of men were involved in the creation of statues, an individual statue took a team of between 5 and 6 men approximately a year to complete.