Raw stone from Zimbabwe: We have
in stock dark green and light green opal, also spotty opal, lemon
opal, greenish/yellowish/purplish fruit serpentine, brown and black
serpentine, multi-coloured cobalt, purple lepidolite, dark green
verdite and black springstone. Verdite and lepidolite are semi-precious
stones which can also be used for jewellery making.
The different types of opal and the fruit serpentine are suitable
for beginners as they are quite soft. More experienced sculpturs
will also be interested in the hard stones: black springstone, lepidolite
and verdite, also cobalt which can be a bit tricky to carve due
to its iron deposits but which has lots of character and glorious
We are open by appointment throughout the year and during workshops.
If you can only come weekends, no problem. Please contact Renate
on Tel: 01273 565404 or e-mail: email@example.com
Below are some examples of works produced by experienced artists
achieved in a 2-day workshop.
The stone comes from
the hills of the Great Dyke, a volcanic ridge that runs 310 miles
through Zimbabwe's countryside - the longest linear mass of volcanic
rock in the world. The rocks on these hills are interlaced with copper,
chrome, platinum, gold, emeralds and other precious metals. Heat and
pressure exerted on these 2.5 billion year old rocks caused unusual
mineral combinations. These are reflected in the many variations of
coloration, shadings and density of stone.
The stone is quarried
with handtools: pickaxe, prybar, punch and hammer. The harder the
stone, the more difficult the process.
Rated on the universally
used Mohs Scale of Hardness (1 and below is talc, up to 10 is diamond),
serpentine and springstone (the hard end of serpentine) ranges from
2.0 to 5.5. Opal and fruitstone is at the lower end of this range.
The properties of these raw stones from Zimbabwe make them ideal for outdoor sculptures or fountains. Unlike many stones, which deteriorate under outdoor conditions, these stones are impervious to temperature changes and acid rain. In the winter,especially when it is frosty, it is advisable to bring your sculpture indoors or protect it with some insulating material (such as an old blanket) covered in polythene. To give the sculptures their highly polished appearance, the artists heat the stone with a blowtorch or other heat source and apply wax (Cobra in Zimbabwe, Briwax in the U.K.) until it is absorbed by the stone. This process may be repeated a couple of times but it is important to allow the stone to cool down in between. Once cool but not cold to the touch, the sculpture is buffed to a shine with a soft cloth.
process may be necessary if your own sculpture becomes a little dull
after a few years. If the sculpture is small enough, it is safe to
put in a hot oven for between 3 and 10 minutes, depending upon size,
before applying wax as before. The stone has to be hot enough to melt
the wax but not so hot that it cracks. It is best to take it out of
the oven every few minutes to check. Bigger sculptures can be warmed
by using a blowtorch or gas or electrical paint stripping tool but
care needs to be taken that the heat is evenly applied and not concentrated
on any one spot..