The small Neolithic sandstone human figurine is believed to be up to 5,000 years old.
Experts have described the find as one of "astonishing rarity".
Archaeologists made the discovery - measuring just 3.5cm by 3cm - at Historic Scotland's excavation at the Links of Noltland.
It is believed to be the only Neolithic carving of a human form to have been discovered in Scotland - with only two others said to have been found elsewhere in the UK.
The carving is flat with a round head on top of a lozenge-shaped body. The face has heavy brows, two dots for eyes and an oblong for a nose. It is thought other scratches on top of the skull could be hair.
“It was one of those Eureka moments. The discovery of a Neolithic carving of a human was quite a moment for everyone to share in”
Richard Strachan Historic Scotland
A pair of circles on the chest are being interpreted as representing breasts, and arms have been etched at either side.
It is believed a regular pattern of crossed markings on the reverse could suggest the fabric of the woman's clothing.
Richard Strachan, project manager and senior archaeologist with the Historic Scotland cultural resources team, said: "The find was made by archaeologist Jakob Kainz.
"It looked like the stone had been carved. As some of the mud crumbled off he saw an eye, then another and a nose, then a whole face staring back.
"It was one of those Eureka moments, none of the archaeology team have seen anything like it before, it's incredibly exciting. The discovery of a Neolithic carving of a human was quite a moment for everyone to share in."
Culture Minister Mike Russell said: "This is a find of tremendous importance - representations of people from this period are incredibly unusual in Britain.
"What we are seeing here is the earliest known human face in Scotland. It once again emphasises the tremendous importance of Orkney's archaeology and also of the Links of Noltland site."
The building being excavated was once a farmhouse, standing in a network of fields.
Story from BBC NEWS:
Published: 2009/08/21 05:52:49 GMT
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