Archaeo-optics in Orkney Day 13: Quartz at the Tomb of the Eagles

In my experience, outcropping veins of quartz are uncommon in Orkney. But I did remember reading in 'A Celebration of Sunrise at the Tomb of the Eagles', by Babette Barthelmess, that quartz can be found among the rocks outside this site. Ronnie and I went to investigate...

Remarkable rock formations overlooked by the Tomb of the Eagles (Photo: Aaron Watson)
 
Ronnie recording the quartz outcrop with the Tomb of the Eagles beyond (Photo: Aaron Watson)
 

The presence of the quartz is interesting given its proximity to the nearby chambered cairn. Quartz veins were sometimes quarried, but we could see no evidence for this. Quartz might also have contributed to ritual activities within the darkened spaces of chambered cairns as under certain conditions it can emit light through a chemical process known as triboluminescence.