Halite

Product Details

What is Halite?

• Chemistry: NaCl, Sodium Chloride • Class: Halides • Uses: Major source of salt and as mineral specimens. Halite, better known as rock salt, can easily be distinguished by its taste. Since taste is an important property of salt, there is a right way to taste a specimen of halite (or an unknown mineral that is similar to halite) and a wrong way. The right way is to first lick your index finger, rub it against the specimen and then taste the finger. This limits the amount of the mineral that actually gets in your mouth, an important consideration when you consider that there are poisonous minerals that resemble halite. Halite is found in many current evaporative deposits. It is also found in ancient bedrock all over the world where large extinct salt lakes and seas have evaporated millions of years ago, leaving thick deposits of salt behind. Perfectly formed cubes of halite are typical of the habit of this mineral. However it does form some unusual interesting habits that are much sought after by collectors. One habit is called a hopper crystal which forms what has been termed a skeleton of a crystal. Just the edges of a hopper crystal extend outward from the center of the crystal leaving hollow stair step faces between these edges. Hopper crystals form due to the disparity of growth rates between the crystal edges and the crystal faces. Often specimens are brightly colored purple and blue and with the silky luster due to the fibers, they represent a wonderful and a very uncharacteristic variety of halide. These specimens are a must have for teachers of mineral identification classes that want a stumper for those end of the session ID exams. Of course they are still easy to identify with the oft forgot simple taste test. Well crystallized specimens of halite cubes can be very impressive and popular. Some are colored an attractive pastel pink by inclusions of bacterial debris that are trapped during crystallization in an evaporative lake. Often these specimens that are sold world wide in rock shops and in mineral shows where grown within the past year. In fact, the crystals form so fast and so well in some evaporative lakes that mineral dealers are using their imaginations to enhance their inventory. They are putting sticks, animal skulls and other imaginative items into these lakes and retrieving them a relatively short time later covered in clusters of white or pink halite cubes. Halite is a soft mineral that flows easily under pressure. At depths of as little as 3 kilometers, it begins to rise through the rocks above it in cylindrical plugs called salt domes. These are of interest to oil prospectors because petroleum collects around them.