-   Allan Fraser

-  October 2002

Witwatersrand Gem & Mineral Club
Outing to Syferfontein Calcite Mine, Nylstroom in October 2002

We arrived at the Syferfontein Calcite quarry at around 10h00. It was a hot day however much cooler than we had all anticipated as the day before most of the country was experiencing a heat wave. The Syferfontein Calcite Mine is located east on Nylstroom on the Springbok Flats. The area consists chiefly of a series of basalts making up what is known as the Stromberg Basalts. The basalts are of Jurassic age (~180 million years old).

The old calcite quarry is no longer mined and is now filled with water and is adjacent to a 50 meter high dump made up of waste material deposited there during mining operations. In the distance the Syferfontein Processing Plant was in operation and we tried to ascertain where the calcite was being mined today. On arrival we all dispersed onto the dump and spent around 2 hours searching through a lot of material. Elia came across a large boulder of basalt which and we proceeded to break up with our hammers. We split the rock in two and found exposed large rosettes of pink Stilbite. The basalts at the quarry contain lovely dark to light pink stilbite rosettes and a variety of other minerals possibly zeolites, chlorite and calcite. Of interest was the pipe amygdales found in many of the basalt rocks we broke open. One person managed to carefully pry open a rock and with great delicacy remove a Y-shaped pipe amygdale from the basalt matrix. These pipe-like tubes are apparently formed off the base of the lava flow as gas is being emitted from the molten lava. The tubes then get filled with secondary minerals such as zeolites, chlorite and opal. Several of these pipes contained a clear to pink mineral. Also found were very delicate tiny green filament-like structures within small (~0.5 cm) vugs in the basalt. The basalt exposed was so highly weathered that one could very easily break a boulder with a gentle strike from a rock hammer. Large chunks of calcite were found and as I discovered after I broke a piece open, can be quite sharp as I cut my hand in the process of lifting up the freshly exposed surface.

Pink Stilbite in Stromberg Basalt from Syferfontein Calcite Mine


Digging away at a large basalt bolder containing beautiful pink sprays of stilbite and calcite. This bolder is today in my collection. The rockhounds in the picture are from left to right, Ray Biram, Nicolas Grech-Cumbo and Elia Pedersoli

At around 11h30 we all decided it was time to take a break for lunch and besides I was thinking of those chilli samoosas in my back-pack. Elia moved his vehicle to a large tree some distance away and proceeded to prepare for lunch. Within minutes he had set up a portable table and had started a fire using a few calcite rocks as a windshield. In true Italian fashion a formidable feast of salame, parma ham, sausages, bread, meat and a sweet frizzante Italian white wine was laid on the table.

The feast afterwards

Soon the group were enjoying the feast and exchanging rock hound stories. After lunch a few of us searched another area near the dump and found much of the same material. A great outing! A BIG thank you to Elia for arranging for us to visit the site and for the very memorable lunch and frizzante!

Never mind about the calcite and all the micro mount stuff. Pretoria Club has offered to pay membership fees for Elia for the next 5 years, on condition he joins their club and goes on at least one outing a year and supplies the food. Elia, that was fantastic... Thank you very much. Kevin Hean.