Chapter 6

Application by the British Volcanology Society (BVS) and the Icelandic Geological Project (IGP) to undertake excavations in Vindahellir Lava Tube, in the Hrafndalur Valley, Grímsvötn.

Since the October 2013 discovery of Vindahellir, geologists have been confounded by the large, unidentified crystal, now named neckerite, found embedded in one of the passage walls. The recent exploration of a larger second entrance to the lava tube raised the possibility of performing further in depth analysis of the crystal.

In September 2014, IGP members Björn Sigurdsson and Arnar Helgason, along with BVS member Dr Debbie Austin, transported a superviolet scanning machine, adapted for use in the field, through the larger passages of the second entrance to the site of the neckerite.

Scanning results showed that the deposit comprises a sphere a metre and a half across, of which only a small segment protrudes from the wall.

The neckerite is hypothesised to be a carbon isomer, similar to, but harder than, diamond. Its molecular composition and the mechanism of its formation remain unknown. But its hardness (it is resistant to all available sampling methods) and its lack of tactility (expedition members report that it does not seem to possess any sort of texture at all) render it unique among known volcanic minerals.

Since no field instruments are capable of taking samples from the deposit and other analytical instruments are too large to be miniaturised for use underground, permission is sought to drill the surrounding rock from the neckerite and extract the sphere intact, through the second entrance. Damage to the lava tube would be restricted to the sample site; the remaining passages need not be enlarged.

The IGP laboratories in Reykjavik do not possess the range of instrumentation required to analyse the neckerite. Therefore permission is also sought to temporarily export the sample to the United Kingdom, to enable investigation by the BVS team in Cambridge, led by Dr Debbie Austin.