Simple identification and quantification of microdiamonds in rock thin-sections
Massonne, Hans-Joachim; Bernhardt, Heinz-Jürgen; Dettmar, Dieter; Kessler, Ellen; Medenbach, Olaf; Westphal, Tanja
European Journal of Mineralogy Volume 10 Number 3 (1998), p. 497 - 504
published: Jun 22, 1998
manuscript accepted: Dec 23, 1997
manuscript received: Apr 8, 1997
ArtNo. ESP147051003010, Price: 29.00 €
Abstract Using a method of preparing polished thin-sections described in this paper, we are able to detect microdiamonds in high-pressure metamorphic rocks quickly and quantitatively by a distinctive striation pattern on the polished surface of the thin-section. We present results on samples from diamondiferous gneiss and marble of the Lake Kumdy-Kol region of the Kokchetav Massif, Northern Kazakhstan. Our method clearly reveals microdiamonds as small as l μm by a striation pattern as soon as they emerge on the surface during the polishing procedure. The striation pattern on the polished surface disappears almost immediately after extraction of the microdiamond that caused it. More than six hundred polished thin-sections of various kinds of igneous and metamorphic rocks mostly without a high-pressure origin were examined, but this type of striation pattern was found in less than 1 % of these. In such examples the striations could also be due to the contamination of diamond from external sources.