Altar stone (Stonehenge)
Encyclopedia
The Altar Stone is a central megalith
at Stonehenge
in England
, dating to Stonehenge phase 3i, around 2600 BC. It is made of a purplish-green micaceous sandstone
and is thought to have originated from outcrops of the Senni formation of the Old Red Sandstone
in Wales
, though this is currently in debate. Stone 80 (Altar Stone) was most recently excavated in the 1950s, but no written records of the excavation survive. Stone 55 (a sarsen megalith) lies on top of Stone 80 perpendicular, thought to have fallen across it. The Altar Stone weighs approximately six tons and would have stood nearly two meters tall. It is sometimes classed as a bluestone
, because it does not have a local provenance. Now recumbent, it is thought to have originally stood as a single large monolith.
Megalith
A megalith is a large stone that has been used to construct a structure or monument, either alone or together with other stones. Megalithic describes structures made of such large stones, utilizing an interlocking system without the use of mortar or cement.The word 'megalith' comes from the Ancient...
at Stonehenge
Stonehenge
Stonehenge is a prehistoric monument located in the English county of Wiltshire, about west of Amesbury and north of Salisbury. One of the most famous sites in the world, Stonehenge is composed of a circular setting of large standing stones set within earthworks...
in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, dating to Stonehenge phase 3i, around 2600 BC. It is made of a purplish-green micaceous sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and is thought to have originated from outcrops of the Senni formation of the Old Red Sandstone
Old Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
in Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
, though this is currently in debate. Stone 80 (Altar Stone) was most recently excavated in the 1950s, but no written records of the excavation survive. Stone 55 (a sarsen megalith) lies on top of Stone 80 perpendicular, thought to have fallen across it. The Altar Stone weighs approximately six tons and would have stood nearly two meters tall. It is sometimes classed as a bluestone
Bluestone
Bluestone is a cultural or commercial name for a number of dimension or building stone varieties, including:*a feldspathic sandstone in the U.S. and Canada;*limestone in the Shenandoah Valley in the U.S...
, because it does not have a local provenance. Now recumbent, it is thought to have originally stood as a single large monolith.