Disk patterns on diamond from the Arkhangelskayakimberlite pipe
Vasiliev E. A., Kriulina G. Yu., Garanin V. K.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2016. V. 145. N 5. P. 71-74
The perfectly round negative etch sculptures have been found on the rounded surface of a diamond from the Arkhangelskaya kimberlite pipe. These sculptures have the form of negative discs from 2 to 70 μm in diameter, and down to 4 μm in depth. The larger disks have a flat bottom, disks with a diameter lesser than 10 microns are wedging out in depth, down to trigonal pits in the limit. Discs may be primary and/or secondary in relation to the adjacent surfaces of the dissolution. Round negative sculptures might occur after etching under the diamond wetting droplets or bubbles in a heterogeneous melt. The rarity of these sculptures is due to a unique combination of factors—interaction of a heterophasic melt in the disequilibrium diamond PT conditions with the fresh cleavage surface. Similar, but positive sculptures were previously observed, so the corrosive and protective action of such droplets or bubbles is possible.
Key words: diamond, dissolution, disks, etch pits, Arkhangelskaya pipe.