At Balnuaran of Clava itself there is a group of three Bronze Age cairns which lie close together in a line running north east to south west. The tombs at either end are of the passage grave sub-type. The central cairn is of the ring cairn sub-type, and uniquely has stone paths or causeways forming "rays" radiating out from the platform round the kerbs to three of the standing stones. The cairns incorporate cup and ring mark stones, carved before they were built in to the structures. The kerb stones are graded in size and selected for colour, so that the stones are larger and redder to the south west, and smaller and whiter to the north east. All these elements seem to have been constructed as one operation and indicate a complex design rather than ad hoc additions.
The ring round the northern Balnuaran of Clava cairn was measured and analysed by Professor Alexander Thom. He found that the ring was slightly egg-shaped with a complex geometry of circles and ellipses which could be set out around a central triangle, using sizes which are close to whole multiples of what he called the Megalithic yard. While the geometry of the shape is generally accepted, the Megalithic Yard is more controversial.
- grid reference NH757445
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