WITWATERSRAND
GEM and MINERAL CLUB
P O Box 3708 Cresta 2118 South Africa
Room 215 G, 2nd floor Department of Geology University of Johannesburg Auckland Park
JUST A WORD FROM THE EDITOR
April means Easter which entails a weekend away with fellow rock hunters. The Easter Weekend sees the 50th
Gemboree to be held in Nelspruit, hosted by the WGMC. To all our
club members who will be joining in the weekend’s activities, please
travel safely, and enjoy the weekend.
To all the April born club members - wishing you all a blessed year
ahead. Happy Birthday to Sharon Waddington (3rd), Monique van
Deventer(14th), Owen Garvie(21st), Grant Kelbrick(25th) and Ockert
Schoeman(25th).
There are still a few club members who have not paid their 2017 club membership fees to date. Kindly note that to
be fair to all members, those who have not made payment this month will be removed from the mailing list and will
no longer receive information regarding club meetings/activities/events, nor have the right to collect the 2017
FOSAGAMS magazines.
EVENT CALENDAR
THEMED EVENING :– 12th April 2017 : Please bring a minimum of 3 specimens of the following themes:
1. Beryl from African localities
2. Single Crystals – no clusters or matrix
At the meeting of the 26th April 2017 you can learn more about how minerals are formed and crystals grow.
John Rakovan presented a talk at the Dallas Symposium in 2016 on this theme. Join us as we view his presentation
(DVD). This evening would also be a social evening with a SWOP & SELL.
50th GEMBOREE 2017: Easter Weekend, 14-17 April 2017 at Nelspruit. All bookings are now closed, however should
you still wish to purchase a t-shirt/s kindly order directly on [email protected] at R100.00 per shirt (good
quality fabric, navy coloured).
WGMC Year-end evening: 29th November 2017 (members only)
WGMC will be celebrating its 60th anniversary in 2018 (founded in 1958)
1
BERYLS FROM AFRICAN LOCALITIES
Beryl is often unknown to the general public, even the gemstonebuying public. However, it is one of the most important gem
minerals.
Beryl is a mineral composed of beryllium aluminium cyclosilicate
with the chemical formula Be3Al2(SiO3)6. Well-known varieties of
beryl include emerald and aquamarine. Naturally occurring,
hexagonal crystals of beryl can be up to several meters in size, but
terminated crystal are relatively rare. Pure beryl is colourless, but
it is frequently tinted by impurities; possible colors are green,
Three varieties of beryl:
blue, yellow, red, and white (https://en.wikipedia.org/wiki/Beryl).
morganite, aquamarine and heliodor
Without these splendid colour varieties, beryl would be a rather
ordinary gemstone with only average fire and brilliance. Emerald
is the green variety and Aquamarine is the blue variety of beryl. Other colours of beryl are also used as gemstones
but are not as well known:
• The greenish-yellow variety is called Heliodor.
• The pink variety is called Morganite.
• The colourless variety is called Goshenite.
• The name beryl is used for the red and golden varieties, which are simply called red beryl and golden beryl,
respectively.
PHYSICAL CHARACTERISTICS OF BERYL:
• Colour is varied and includes emerald green, blue to blue-green, yellow, greenish-gold, red, colourless & pink
• Luster is vitreous
• Transparency: Crystals are transparent to translucent
• Crystal System is hexagonal - 6/m 2/m 2/m
• Crystal Habits typically include the hexagonal prism with pincoid terminations. The terminations are often
modified by many different pyramidal faces which can sometimes produce a rounded termination in the
rough shape of a used pencil eraser.
• Cleavage is imperfect in one direction (basal)
• Fracture is conchoidal
• Hardness is 7.5 - 8
• Specific Gravity is approximately 2.6 - 2.9 (average)
• Streak is white
• Other Characteristics: Faces on large crystals are often pitted, striated lengthwise and rough.
• Associated Minerals include micas, quartz, euclase, calcite, tourmalines and some feldspars.
• Notable Occurrences include Colombia and some African localities for emerald; Brazil, Russia and Pakistan
for aquamarine; California, Brazil, Africa, and many other localities for other beryl’s.
• Best Field Indicators are crystal habit, lack of good cleavage, hardness and colour.
(http://www.galleries.com/Beryl)
The name "beryl" is derived from Greek beryllos which referred to a "precious blue-green color-of-sea-water stone".
The term was later adopted for the mineral beryl more exclusively.
When the first eyeglasses were constructed in 13th century Italy, the lenses were made of beryl (or of rock crystal)
as glass could not be made clear enough. Consequently, glasses were named Brillen in German (bril in Dutch and
Briller in Danish).
Beryl of various colours is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural
Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in
2
Europe in Norway, Austria, Germany, Sweden (especially morganite), Ireland and Russia, as well as Brazil, Colombia,
Madagascar, Mozambique, Pakistan, South Africa, the United States, and Zambia. US beryl locations are in
California, Colorado, Connecticut, Georgia, Idaho, Maine, New Hampshire, North Carolina, South Dakota and Utah
(https://en.wikipedia.org/wiki/Beryl).
Common Mineral Associations with Beryl are Quartz, Muscovite, Albite, Orthoclase, Calcite, Pyrite, Spodumene,
Tourmaline and Apatite (http://www.minerals.net/mineral/beryl.aspx).
Beryl (variety aquamarine) with Schorl
Parallel growth of crystals, some of them
doubly terminated, very bright, with
excellent blue color, more intense than
usual with samples from this locality and
with neat and bright terminations. On the
Aquamarine there are small crystals, very
well defined, of Schorl. Erongo Mountain,
Usakos, Erongo Region Namibia (1990)
http://www.fabreminerals.com/search_show.php?SECTION=RSSA
C&CODE=MA90R6
Goshenite with included Albite
Goshenite is the clear, colourless variety of
Beryl. On this specimen, the bottom two
thirds of the main crystal have included Albite
which gives it a brown color. The main crystal
has a very high luster. The termination is flat
except near the middle where it is recessed
and composed of several small, hexagonal
terminations. At the base of the Goshenite is
a Quartz crystal which has Tourmaline both
included in it and on its surface. Erongo
Mountain, Erongo Region, Namibia
Beryl (Var: Aquamarine), Schorl
An example of aquamarine with schorl
from one of the lesser known African beryl
locations - the Jos Plaeau of Nigeria. The
upper two-thirds of the aquamarine is
water-clear, gemmy, with great blue
colour intensity and a fine, modified,
pinacoidal termination. The aquamarine is
superbly accented with lustrous schorl
crystals, embedded on the sides, and
included in the interior.
http://www.irocks.com/minerals/specimen/12167
http://www.mwminerals.com/m1749_Goshenite_included_Albite.ht
ml
READ MORE:
• https://www.mindat.org/minloclist.php?m=819&l=21891 (list of Beryls from Zimbabwe)
• http://www.minerals.net/mineral/beryl.aspx
• http://webmineral.com/data/Beryl.shtml#.WN-ET2xMRMs
• http://geology.com/minerals/beryl.shtml
SINGLE CRYSTALS
A single crystal or monocrystalline solid is a material in which the crystal lattice of the
entire sample is continuous and unbroken to the edges of the sample, with no grain
boundaries. The absence of the defects associated with grain boundaries can give
monocrystals unique properties, particularly mechanical, optical and electrical, which
can also be anisotropic, depending on the type of crystallographic structure. These
properties, in addition to making them precious in some gems, are industrially used in
technological applications, especially in optics and electronics.
Mangan Vesuvianite Jeffrey
Mine, Asbestos, Quebec, Canada
Translucent to transparent
complete single crystal with
deep purple coloration
Because entropic effects favor the presence of some imperfections in the
microstructure of solids, such as impurities, inhomogeneous strain and
crystallographic defects such as dislocations, perfect single crystals of meaningful size
are exceedingly rare in nature, and are also difficult to produce in the laboratory,
though they can be made under controlled conditions. On the other hand, imperfect
single crystals can reach enormous sizes in nature: several mineral species such as
3
beryl, gypsum and feldspars are known to have produced crystals several meters
across (https://en.wikipedia.org/wiki/Single_crystal).
A Single Crystal is an individual crystal that has a continuous crystal lattice and is
characterized by anisotropy of its properties. The external shape of a single crystal
is determined by its atomic-crystalline structure and the conditions of
crystallization. A single crystal often acquires well-defined natural faceting; under
nonequilibrium conditions of crystallization, the faceting is weakly manifested.
Single crystals of quartz, salt, Iceland spar, diamond, and topaz are examples of
faceted natural single crystals. Polycrystals and polycrystalline aggregates, which
consist of a set of small single crystals of various orientation, are distinguished
from single crystals.
Smoky Quartz
Tessin (Ticino), Switzerland
Water-clear, delicately colored,
and brilliantly lustrous this
floater quartz is very impressive
for a single crystal. It shows
typical Alpine character with no
downsides. At the back of the
crystal, is some lovely mica as
well as some rutile needles.
Single crystals are valuable as materials that have special physical properties. For
example, diamond and borazon are extremely hard, fluorite is transparent to a
broad range of wavelengths, and quartz is piezoelectric. Single crystals can change
their properties under the influence of external factors (light, mechanical strains,
electric and magnetic fields, radiation, temperature, or pressure); therefore,
products and components made from them are used as various types of
transformers in radio electronics, quantum electronics, acoustics, and computer technology. Originally, natural single
crystals were used in engineering, but supplies are limited and the quality is not always sufficiently high. At the same
time, many valuable properties have been found only in synthetic crystals. Therefore, the necessity of growing
crystals artificially has arisen. The parent substance for growth of single crystals may be a solid (particularly a
powder), a liquid (melt or solution), or a gas (http://encyclopedia2.thefreedictionary.com/Single+Crystal).
THE FORMING OF CRYSTALS (month end topic)
I have found some interesting websites regarding this topic. Click on the links below to read more:
• https://en.wikipedia.org/wiki/Crystal
• http://www.smithsonianeducation.org/educators/lesson_plans/minerals/minerals_crystals.html
• http://pixiecrystals.com/crystal-articles-how-do-crystals-grow.php
LIST OF SOUTH AFRICAN MINERALS FOUND
To assist you with creating a list of minerals found in South Africa for cataloguing purposes, click on the link below:
http://gem5.com/tag/south-africa/
HUMAN ACTIVITY CREATES NEW MINERAL SPECIES
An article was published on the website mining.com on the 1st March 2017 regarding how human activities
around the world have created new mineral species. The International Mineralogical Association have
officially recognized 208 new minerals species.
Many of the recognized minerals originated in ore dumps, through the weathering of slag, formed in tunnel walls,
mine water or timbers, or through mine fires. Six were found on the walls of smelters and three formed in a
geothermal piping system. Read more regarding this at http://www.mining.com/human-activity-creates-208-newmineral-species/. Thank you to Bruce Cairncross for sending this article through.
4
CLUB MEETINGS
The club meets every second and last Wednesday of each month at 19h00 for 19h30, excluding December, at the
University of Johannesburg, Auckland Park, Department of Geology, Second Floor, Room 215G. Please use the
entrance off Ditton Road, the building is directly opposite the mentioned entrance and parking is available to the left
(limited) or around the turning circle to the right (plenty available). We welcome all visitors. Tea, coffee, and biscuits
are available at a donation of R5.00.
MEMBERSHIP
The Annual membership fees for 2017, payable by end of March 2017, are as follows:
• Full/Family Member
R250 per year (note: the family member has no voting right at AGM)
• Pensioner Member
R150 per year
• Students
R90 per year
Kindly pay your club fees and forward the proof of payment to [email protected] . This will enable you to
continue to participate and enjoy the club’s benefits.
Fees are payable to the Treasurer, Jono Hotz. The WGMC Banking details are as follows:
Standard Bank
Cheque account
Account number:
200551744
Branch code:
006305
COMMITTEE MEMBERS
The following club members were elected on the AGM of the 22nd February 2017. Your committee members are:
Chairman
Massimo Leone
082 372 0328
[email protected]
Vice Chairman
Stephen Gomersall
082 774 0746
[email protected]
Treasurer
Jono Hotz
082 444 9628
[email protected]
Editor & Secretary
Claudette Denner
072 591 6202
[email protected]
Other Club Contacts (non-committee members)
• Raffle Master
Keith Bailie
• Mineral Section
Damian Kislig
• Librarian
Shan Smit
• Facebook Page
Stephen Gomersal
082 928 9515
072 203 1351
082 221 6619
082 774 0746
LIBRARY
The club has a range of mineral books and magazines which could be taken from the Library. This can be done during
our meetings. Kindly note that Shan Smit has accepted to be the club’s librarian for 2017. For more information on
the books and magazines available please contact him on 082 221 6619 or [email protected].
Should you have any books (old or new) on minerals, geology or lapidary that you wish to donate to the library,
please contact our new Librarian to donate.
RAFFLE
The monthly raffle takes place on the last Wednesday of every month. Raffle tickets are on sale in the meeting room
on the night at R10.00 each. Proceeds of the raffle goes into the kitty to host a fabulous year end function.
Those selling minerals at the club, please donate some specimens towards the raffle. Contact Keith Bailey at the
club meetings in this regard.
5
LINKED SOCIETIES
We exchange newsletters with the following societies. Should you be interested in reading any of them please
contact [email protected] and I will email them on to you. If you wish to join any of the clubs, or attend
their lectures and outings, please contact the person listed below:
• FOSAGAMS
Linda Stone
[email protected]
• South African Micro-Mount Society
Alison Rose
[email protected]
• Natal Mineral & Gem Society
Frank Farquharson [email protected]
• Pietermaritzburg Gem & Mineral Club Craig A’Bear
[email protected]
• Nelspruit Gem & Mineral Club
Paul Vermaak
[email protected]
• Pretoria Gem & Mineral Club
Willem Vorster
[email protected]
• Cape Town Gem & Mineral Club
Malcolm Jackson [email protected]
• Kimberly Lapidary Club
Ludi von Bezing [email protected]
FOSAGAMS has a website, which provides information about all the affiliated clubs, outings, back issues of the
magazine, gallery of photos of outings and many more. For more information on the hobby browse the following link
http://www.fosagams.co.za/
ADVERTS
If you are a club member and you wish to advertise your mineral or
related type business, please email the editor your details/advert
layout to publish it in the monthly newsletter.
DISCLAIMER
A selection of hand and head sized
specimens available for sale. Please contact
Sharon on 082 923 4794
www.stores.ebay.com/sahotrocks
If you have received this email in error, or wish to be added/removed
from our mineral related mailing list, please REPLY to
[email protected] with subscribe or unsubscribe in the
subject line.
AT THE END
Thank you for taking the time to read the WGMC newsletter.
Remember that if you have something to add or share with your fellow rock hounds please feel free to email the
details to [email protected] .
Rock on!!!
Claudette Denner
Wits Gem & Mineral Club
Newsletter Editor
6