Gypsum, one of the most widely used
minerals in the world, literally surrounds us every day.
Mostly gypsum is used to make wallboard for homes, partition
boards for offices which has become a common norm for all modern
offices to be separated with Soft Gypsum boards and also
commercial buildings; a typical new home contains more than 7
metric tons of gypsum alone. Moreover, gypsum is used worldwide in
concrete for highways, bridges, buildings, and many other structures
that are part of our everyday life. Gypsum also is used
extensively as a soil conditioner on large tracts of land in suburban
areas, as well as in agricultural
In Tanzania 99.5% of all the
Bungalows, Flats and High Rise Buildings in Cities are build using
bricks made from Cement, and this Cement is made from Gypsum
unearthed from Makanya.
COMPOSITION:
Hydrous calcium sulfate (32.6% CaO,
46.5% SO3, 20.9% H20).
DISTINGUISHING
CHARACTERISTICS:
Gypsum is usually white, colorless or gray, but can also
be shades of red, brown and yellow. Gypsum has several variety names
that are widely used in the mineral trade. The three we see most are
Selenite, Satin Spar and Alabaster. Gypsum is a major rock forming
mineral that produces massive beds, usually from precipitation out of
highly saline waters. These beds are softer than those of anhydrite or
marble, and gypsum will not bubble in acid. Since it forms easily from
saline water, gypsum can have many inclusions of other minerals and even
trapped bubbles of water and air. Gypsum crystals can be scratched with
a finger nail which is about the only test needed. The clear plates bend
but lack the elasticity of mica, and are softer than brucite. Thin
crystals are flexible but not elastic, meaning they can be bent but will
not bend back on their own. Crystals are often fluorescent yellow,
showing hourglass pattern within crystal. They may also be
phosphorescent.
ENVIRONMENT:
Gypsum is one of the more common
minerals in sedimentary environments. It occurs in massive beds, as free
crystals in clay beds and crystallized in limestone
cavities.
CRYSTAL DESCRIPTION:
"Selenite" is the colorless and
transparent variety that shows a pearl like luster. Crystals are common
and most often assume a tabular habit. Fish tail twins are
characteristic and spear head twins or swallow tail twins are also
formed. The commonest crystals are found loose and free-growing in clay
beds, coming out whole. "Satin Spar" comes from compact fibrous
aggregate veins. This variety has a very satin like look that gives
these crystals a play of light. "Alabaster" is A fine grained massive
material used for centuries in ornamental stone carving. Other Crystal
Habits include bladed or blocky crystals with a slanted parallelogram
outline. Long thin crystals show bends and some specimens bend into
spirals called "Ram's Horn Selenite". Also massive, crusty, granular,
earthy and fibrous.
TESTS:
Tests: Soluble in hot dilute
hydrochloric acid; the addition of barium chloride solution makes a
white precipitate. After firing, fluorescent and phosphorescent in
long-wave ultraviolet light.
LOCALITIES:
Gypsum is a widespread, commercially
important mineral. The massive beds are quarried, or mined, for the
manufacture of plaster of Paris and various plaster products such as
sheet rock. Abundant deposits which have formed from the alteration of
the water-free variety, anhydrite. Are mined for their economic
applications, in New York State, Michigan, Texas, Iowa, California, Nova
Scotia, Mexico, Australia and many more localities.
GYPSUM IN TANZANIA
DEPOSITS
In Tanzania Gypsum is found
in huge volumes in a place called Makanya the area within Mwanga
District. Its deposits are within the Mwanga District, Mwanga
falls within the Kilimanjaro Region in Tanzania. Mostly the Gypsum at
this site of Makanya is unearthed using purely primitive
local tools. Since its rocks are very soft they are easier to be
mined without the use of Dynamites etc. It also depends with
the Buyer request since we can also crush the Gypsum into Powdery
format mode but this will mean more purchase costs for the buyer. Our
Machines can crush Gypsum soft rocks into 5mm sizes or crush it
completely to powdery format.
All the Major Cement
companies in Tanzania such as Tanga Cement in Tanga Region, Wazo Hill in
Dar es Salaam,Mbeya Cement Ltd in Mbeya Region they all use Gypsum from
Makanya as their Raw Material for Making Cement, Infact 99%
percent of all Industries in Tanzania they use the Soft Rocks (Gypsum)
from Makanya for the Cement production.
Gypsum purity content
of Makanya is 70%, Its completely suitable for the production
of Cement, Office Partition Soft boards etc.
After its Discovery the
Government had to improve the transport network between Makanya
and other Regions in Tanzania where Cement Industries are based. Infact
its only about 20 minutes from the Mines to the Railway station
center.From the Railway station its shipped mostly to to different
regions in Tanzania where there is plants for Cements Productions,. Also
its shipped to Dar es salaam the capital city for the local use or for
the Exportation purpose use. In Dar es Salaam there is an international
port with all the International qualities for parking huge cargos at the
Ships. Mostly the Cranes here they can lift up to only 50 Tons
containers.
USES:
Sheet Rock wall board, paint fillers, some cements,
plaster of Paris, fertilizer, ornamental Alabaster and as rare mineral
specimens.
FACTS & HISTORY
ABOUT GYPSUM
The name plaster of Paris comes from its early
production from quarries in Montmartre, Paris.
The name gypsum
comes from the Greek word for the calcined or "burned"
mineral.
The word selenite comes from the Greek word meaning moon
rock. A Greek comparison of the pearly luster of the cleavage to
moonlight.
Gypsum is used in drywall because it has very low
thermal conductivity Which makes it a good
insulator.
