LISTING
DESCRIPTION
Gypsum is a soft sulfate mineral composed
of calcium sulfate dihydrate, with the chemical
formula CaSO4·2H2O.[3] It is
widely mined and is used as a fertilizer, and as the
main constituent in many forms of plaster, blackboard chalk
and wallboard.
DETAILED
DESACRIPTION
A
massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used
for sculpture by many
cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine
Empire and
the Nottingham alabasters of Medieval
England. Mohs scale of mineral hardness, based on scratch Hardness comparison, defines hardness value 2 as gypsum. It forms
as an evaporite mineral and as a hydration product
of anhydrite.
Occurrence
Gypsum is a common mineral, with thick and
extensive evaporite beds in
association with sedimentary rocks. Deposits are known
to occur in strata from as far
back as the Archaean eon.[9] Gypsum is
deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and
sulfate solutions in veins. Hydrothermal anhydrite in veins is
commonly hydrated to gypsum by groundwater in near-surface exposures. It is
often associated with the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[10] Pure gypsum is
white, but other substances found as impurities may give a wide range of colors
to local deposits.
Because gypsum dissolves over time in water, gypsum
is rarely found in the form of sand. However, the unique conditions of
the White Sands National
Monument in the US state of New Mexico have created a
710 km2 (270 sq mi) expanse of white gypsum
sand, enough to supply the construction industry with drywall for 1,000
years.[11] Commercial
exploitation of the area, strongly opposed by area residents, was permanently
prevented in 1933 when president Herbert Hoover declared the
gypsum dunes a protected national monument.
Gypsum is also formed as a by-product of sulfide oxidation, amongst others
by pyrite oxidation, when the sulfuric acid generated
reacts with calcium carbonate. Its presence
indicates oxidizing conditions. Under reducing conditions, the sulfates it
contains can be reduced back to sulfide by sulfate-reducing
bacteria. Electric power stations burning coal with flue gas desulfurization produce large quantities of gypsum as a byproduct from the
scrubbers.
Orbital pictures from the Mars Reconnaissance
Orbiter (MRO) have indicated the existence of gypsum
dunes in the northern polar region of Mars,[12] which were
later confirmed at ground level by the Mars Exploration Rover (MER) Opportunity.
Uses
Gypsum is used in a wide variety of applications:
·
Gypsum board[19] is primarily used as a finish
for walls and ceilings, and is known in construction as drywall, wallboard, sheetrock
or plasterboard.
·
Fertilizer and soil conditioner:
In the late 18th and early 19th centuries, Nova Scotia gypsum, often referred
to as plaster, was a highly sought fertilizer for wheat fields in the United
States. It is also used in ameliorating high-sodium soils.[20]
·
A binder in fast-dry
tennis court clay
·
As alabaster, a material
for sculpture, it was used especially in the ancient world before steel was
developed, when its relative softness made it much easier to carve.
·
A wood substitute in the
ancient world: For example, when wood became scarce due to deforestation
on Bronze Age Crete, gypsum was employed in building construction at locations
where wood was previously used.[21]
·
A tofu (soy bean curd) coagulant, making it ultimately a major
source of dietary calcium, especially in Asian cultures which traditionally use few dairy products
·
Used in baking as a
dough conditioner, reducing stickiness, and as a baked-goods source of dietary
calcium.[23] The primary
component of mineral yeast food.[24]
·
In the medieval
period, scribes and illuminators mixed it with lead carbonate (powdered white lead) to make gesso, which was applied to illuminated letters and gilded with gold
in illuminated manuscripts.
·
In foot creams, shampoos
and many other hair products
·
Impression plasters in
dentistry
·
Used in mushroom
cultivation to stop grains from clumping together
·
Tests have shown that
gypsum can be used to remove pollutants such as lead or arsenic from contaminated
waters.
PRICE
$6.3/KG
OR $2.86/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
e-mail: emeabau@yahoo.com
website: www.franchiseminerals.com
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