Potash

The term "potash" refers to a group of potassium-bearing minerals and chemicals. Potash includes potassium chloride (sylvite), potassium-magnesium chloride (carnallite), potassium sulphate, potassium-magnesium sulphate (langbeinite), and potassium nitrate. The dominant potash product in the market is potassium chloride, or KCl, a naturally occurring pink, salty mineral for which Canada is the leading world producer and exporter. The main use of potash is in the agricultural sector where it is used as a plant nutrient for its potassium content, which is the third major nutrient after nitro-gen and phosphate. Potash plays an important role in the regulation of plant physiological functions; it supports plant growth and primarily enhances the efficiency of plants in the uptake of other nutrients, boosting their nitrogen and phosphate absorption. Industrial potash is used in the manufacture of potassium-bearing chemicals, as an alternative to de-icing salt, and as a water conditioner. Other end uses include detergents, ceramics, chemicals and pharmaceuticals.

The potash industry in Canada employies more than 3400 workers. Production occurred at eight underground mines and two solution mining operations in Saskatchewan, and at one underground mine in New Brunswick. The Canadian potash industry was first developed in the early 1960s with the opening of potassium chloride mines in Saskatchewan. As the result of a series of expansions in the 1970s and 1980s, Canada now ranks as the world's largest producer and exporter of potash.

Canada is the world's largest potash exporter with a 44% share of international trade. The C.I.S. is the second largest exporter, followed by Germany. Canada exports potash to more than 40 countries, although only six countries account for close to 80% of Canada's total potash exports. In 1998, Canadian potash was shipped mostly to the United States (60%) and Asia (25%), with the remainder being sent to Latin America (10%), Oceania (3%) and Europe (2%). Data compiled by Statistics Canada indicated that Canadian potash exports were valued at $2 billion. The United States was the dominant destination for Canadian potash.

[Much of the general information about Potash as been taken from the Potash Commodity Rerport section of the 1998 Canadinan Minerals Yearbook, by Michel Prud'homme, Minerals and Metals Sector, Natural Resources Canada.]
Go to: http://www.potashcorp.com, to learn more about potash, potash mining and potassium.

The Mineral Sylvite

Chemistry: KCl, Potassium Chloride
Class: Halides
Uses: As a major source of potash and as mineral specimens.
Specimens

Sylvite, also called sylvine, is a major source of potassium or potash used in fertilizer products. So great is the need for potassium that sylvite deposits are considered very valuable economically. As a mineral specimen sylvite does not get much attention. The crystals can be well formed and are often reddish due to inclusions of hematite. However, sylvite is very soluble in water and specimens need to be stored in closed containers because even the moisture in the air can degrade its appearance. Never clean a sylvite specimen with water!

Sylvite is closely related to the more common halite, NaCl, and they share so many properties that identification is sometimes difficult. Sylvite commonly has octahedral faces truncating the corners of the cubic crystals. So does halite, but this characteristic is much more prevalent in sylvite than in halite. Better tests include a taste test in which halite, salt, will taste salty and sylvite tastes bitter. This test is good if you need to distinguish one or two specimens, but what if you are testing hundreds of feet of core samples for beds of sylvite verses halite. A good test in those cases is the knife test in which a knife blade when scratched across the surface of the sample will produce a powder in halite and not in sylvite.
The name sylvite is easily confused with the much more valuable sylvanite. Sylvanite is a silver gold telluride, AuAgTe4 and should never be mistaken for sylvite.

Physical Characteristics:

Color is colorless or white, sometimes tinted red, blue or yellow.
Luster is vitreous.
Transparency: Crystals are transparent to translucent.
Crystal System is isometric; 4/m bar 3 2/m.
Crystal Habits are cubes with frequent octahedral faces truncating the corners of the cube, crystals will often have a cavernous appearance from dissolution. More commonly massive and granular.
Cleavage is good in three directions forming cubes.
Fracture is uneven.
Hardness is 2 - 2.5 Specific Gravity is 3.9 - 4.1 (heavier than average for translucent)
Streak is white.

Other Characteristics:

Dissolves easily in water, does not powder when the blade of a knife is scratched across its surface and has a bitter taste, not salty like halite. Associated Minerals include halite, carnallite, kieserite, gypsum, anhydrite and other evaporite minerals. Notable Occurrences include Strassfurt, Germany; Kalush, Russia; New Mexico, Texas and Kern Co., California, USA; Saskatchewan, Canada; France, Mt. Vesuvius, Italy and Spain.

Best Field Indicators are bitter taste, associations and crystal habit. For more information about Sylvite see: http://www.er.gov.sk.ca/Default.aspx?DN=3563,3541,3538,3385,2936,Documents

The Mineral Cancrinite

Chemistry: Na7CaAl6Si6O24(CO3)2 , Sodium Calcium Aluminum Silicate Carbonate.
Class: Silicates
Subclass: Tectosilicates
Group: Feldspathoid.
Uses: Only as mineral specimens.
Specimens

Cancrinite is one of the rarer members of the feldspathoid group of minerals. Minerals whose chemistries are close to that of the alkali feldspars but are poor in silica (SiO2) content, are called feldspathoids. As a result or more correctly as a function of the fact, they are found in silica poor rocks containing other silica poor minerals and no quartz. If quartz were present when the melt was crystallizing, it would react with any feldspathoids and form a feldspar. Localities that have feldspathoids are few.

Cancrinite is unusual in that it is one of the few silicate minerals to have a carbonate ion (CO₃-2) present in its structure. It is because of the carbonate ion that it will effervescence in warm hydrochloric acid. The acid reacts with the carbonate ion to liberate carbon dioxide (CO₂) gas which forms the bubbles. The effervescence is diagnostic as almost no other silicates will do this, although it is common in the carbonates.

Although feldspathoids are known to both extrusive and intrusive igneous rocks, cancrinite is found almost exclusively in intrusive or plutonic rocks. This may be due to the tremendous pressures required to force the large carbonate ions into the structure of cancrinite. Cancrinite will also contain some percentages of sulfate ions (SO₄-2) and chlorine ions (Cl-1); two other large ions. Feldspathoids are similar to zeolites in that their wide open structures allow large ions to be incorporated into them.

Physical Characteristics:

Color is yellow, orange, pink, white or blue.
Luster is vitreous or pearly.
Transparency: Crystals are translucent to more rarely transparent.
Crystal System: Hexagonal; 6 Crystal Habits: Usually massive or granular. Some prismatic to columnar crystals are found. Cleavage is perfect, in three directions, prismatic, but rarely seen in massive specimens.
Fracture is conchoidal to uneven.
Hardness is 5 - 6
Specific Gravity is 2.4 - 2.5 (average)
Streak is white.

Other Characteristics:

Will effervescence in warm hydrochloric acid. Associated Minerals include feldspars such as albite, biotite, hornblende, nepheline, sodalite and other feldspathoids.Notable Occurrences include Kola Peninsula, Russia; Iron Hill, Colorado USA; India; Finland and the Fen region of Norway.

Best Field Indicators reaction to acids, associations, locality and hardness.

More Information about minerals: http://web.wt.net/~daba/Mineral/ or http://www.minerals.net/