Further Data on the Occurrence of Pectolite in Kimberlite

Barbara H. Scott Smith*, Michael E. Skinner and Roger C. Clement
Anglo American Research Laboratories, PO Box 106, Crown Mines 2025, South Africa
Geology Department, De Beers Consolidated Mines Ltd., PO Box 47, Kimberley 8300, South Africa
*Present address: 670 Montroyal Boulevard, Vancouver V7R 2G3, Canada.

Abstract: Pectolite has been identified, using petrographic, chemical, and X-ray methods, in kimberlites from the De Beers and Dutoitspan Mines, Kimberley, South Africa and the Letseng-La-Terai Mine, Lesotho. It occurs as radiating aggregates of fibrous or acicular crystals not only in the groundmass of certain kimberlites but also in altered xenoliths included within kimberlite. The occurrence of Na-rich minerals in kimberlite is unusual. It is suggested that it can occur as an apparently primary mineral resulting from the incorporation and assimilation of foreign Na-bearing material prior to final consolidation, and/or as a secondary mineral after metasomatic introduction of Na-bearing fluids.

Mineralogical Magazine; March 1983 v. 47; no. 342; p. 75-78; DOI: 10.1180/minmag.1983.047.342.13
© 1983, The Mineralogical Society
Mineralogical Society (www.minersoc.org)