Discussions on "Minerals" in "Healthy and Nutritive Foods" forum.
6th Feb 2012, 05:43 PM #1
Minerals are natural compounds formed through geological processes. Minerals are needed by the body in small amounts to help it function properly and stay strong. Iron, calcium, potassium, and sodium are some of essential minerals. Humans need small amounts of about 14 minerals to maintain normal body function and good health.
The 14 minerals that have been shown by research to be essential to human health are: Calcium, Phosphorus, Magnesium, Sodium, Potassium, Chloride, and Sulfur, Iron, Manganese, Copper, Iodine, Zinc, Fluoride, and Selenium. These 14 essential minerals are crucial to the growth and production of bones, teeth, hair, blood, nerves, skin, vitamins, enzymes and hormones; and the healthy functioning of nerve transmission, blood circulation, fluid regulation, cellular integrity, energy production and muscle contraction.
Minerals are neither animal nor vegetable; they are inorganic. Almost all foods contribute to a varied intake of essential minerals. Most minerals are easy to obtain in quantities required by the body. The study of minerals is called mineralogy.
Types of Minerals
There are two types of minerals: Macro minerals and Trace minerals.
- Macro Minerals Macro means "large" in Greek are dietary minerals needed by the human body in high quantities. The macro mineral group is made up of Calcium, Phosphorus, Magnesium, Sodium, Potassium, Chloride, and Sulfur.
- Micro / Trace Minerals Micro minerals, also known as trace elements are micronutrients that are chemical elements. A trace of something means that there is only a little of it. So, even though your body needs mineral each day in small amounts for good health. Scientists aren't even sure how much of these minerals you need each day. Trace minerals includes Iron, Manganese, Copper, Iodine, Zinc, Fluoride, and Selenium.
6th Feb 2012, 05:44 PM #2
Physical Characteristics of Minerals
The physical characteristics of minerals include traits which are used to identify and describe mineral species. These traits include Shape, Color, Streak, Luster, Density, Hardness, Cleavage, Fracture, Tenacity, and Crystal Habit. Each type of mineral is made of a unique group of elements that are arranged in a unique pattern.
However, to identify minerals you don't need to look at the elements with sophisticated chemical tests. Since, a mineral's unique chemical makeup determines its outward characteristics; we can identify minerals by examining their physical properties. Grab an unknown mineral and look for the properties listed below.
- Shape A mineral has a crystal form because of the arrangement of atoms within it. Some minerals do not look like crystals. Mineral has 6 different shapes.
- Color Most people notice the often-beautiful colors of minerals when they first look at them. Minerals can be very beautiful colors. Same type of mineral may be found in a variety of colors. For instance, the minerals quartz can be found in many colors including pink, purple, white or black.
- Luster The term luster refers to the quantity and quality of the light which is reflected from a mineral's exterior surfaces. Minerals may be categorized according to whether they are Opaque or Transparent. Luster describes the way light is reflected by the surface of a mineral. A thin section of an opaque mineral such as a metal will not transmit light, whereas a thin section of a transparent mineral will. Minerals are primarily divided into the two categories of Metallic and Nonmetallic luster. The shiny surface of metals is described as metallic luster. Minerals that have a non-metallic luster can be described as having a glassy, pearly, or dull (earthy) luster.
- Streak Streak is the color of a mineral when it is powdered and it is often different from the color of the whole mineral. Typically an edge of the sample will be rubbed across a porcelain plate, leaving behind a 'streak' of finely ground material. Minerals that come in different colors usually have the same color streak. To powder a little bit of a mineral, you can rub it against a small white piece of porcelain called a streak plate. You can't measure streak with every mineral because you will only get a streak if the hardness of the mineral is less than the hardness of the plate. In a streak sample, however, each of the microscopic crystal grains of the sample is randomly oriented and the presence of an impurity does not greatly affect the absorption of incoming light. Because it is not typically affected by the presence of an impurity, streak is a more reliable identification property than is color.
- Hardness Hardness has traditionally been defined as the level of difficulty with which a smooth surface of a mineral specimen may be scratched. The harder a mineral is, the less likely it is to become scratched. Mohs hardness scale is a relative scale that is used to describe the hardness of minerals. In order to define his scale, Mohs assembled a set of common reference minerals of varying hardnesses and labled these in order of increasing hardness from 1 to 10. The reference minerals of the Mohs scale are as follows:
The Diamond Indentation Method: According to this method, a diamond point is pushed into a planar mineral surface under the weight of a known load. The diameter of the indentation thereby produced is then measured under a microscope. The diamond indentation hardness of a sample is equal to the mass of the load applied divided by the surface area of the indentation produced.
- Density Minerals which formed at the high pressures deep within the earth's crust are in general denser than minerals which formed at lower pressures and shallower depths.
- Cleavage A cleavage plane is a plane of structural weakness along which a mineral is likely to split smoothly. Minerals that have cleavage will break in a certain direction where the bonds between atoms are not strong. If you find a mineral that breaks preferentially in one direction leaving clean flat breaks, it likely has a plane of cleavage. Some minerals have several planes of cleavage in different directions. The quality of a mineral's cleavage refers to both the ease with which the mineral cleaves and to the character of the exposed cleavage surface. The quality of a sample's cleavage is typically described by terms such as 'Eminent,' 'Perfect,' 'Distinct,' 'Difficult,' 'Imperfect,' or 'Indistinct.'
- Fracture Minerals that do not have cleavage will fracture when broken. Fracture takes place when a mineral sample is split in a direction which does not serve as a plane of perfect or distinct cleavage. If the fracture has a smooth curved surface it is called a conchoidal fracture, otherwise most minerals fracture irregularly leaving a wavy uneven break. Fractured surfaces may in some minerals possess a characteristic appearance which can aid in identification. Examples of distinctive types of fracture are 'Conchoidal,' 'Irregular,' and 'Hackly' fracture.
- Tenacity The property of tenacity describes the behavior of a mineral under deformation. It describes the physical reaction of a mineral to externally applied stresses such as crushing, cutting, bending, and striking forces. Adjectives used to characterize various types of mineral tenacity include 'brittle,' 'flexible,' 'elastic,' 'malleable,' 'ductile,' and 'sectile'.
- Crystal Habit The term crystal habit describes the favored growth pattern of the crystals of a mineral species, whether individually or in aggregate. It may bear little relation to the form of a single, perfect crystal of the same mineral, which would be classified according to crystal system.
6th Feb 2012, 05:45 PM #3
Why we need Minerals
We need the minerals for all the chemical processes that go on inside us! If you have ever walked around at very high altitudes (where there is less oxygen in the atmosphere) you will know how breathless you can get. We get Iron from some green vegetables, liver, beef &lots of other sources. It is best eaten from different foods some don't let us absorb it quite so easily by just eating those foods.
Nutritionists are very careful when they say that a nutrient is essential in the human diet. This is particularly true when it comes to minerals, because some minerals taken in high concentrations can be toxic. We can't make minerals in our body; we must ingest them either in our food, our drinking water or in supplements. Most minerals are required in very minute amounts, and proving that a trace mineral is essential for health is a very difficult task.
Everyone at every age needs minerals. A major exception is iron for children under age 4 and adolescent girls and women in the childbearing years. These groups need more iron than a normal diet may provide. Iron is also essential for our blood to be able to carry oxygen round the body - and without oxygen our muscles can't work properly. Iron, for example, found in lean meats, nuts, dried beans, whole grains, and leafy, green vegetables, is necessary for making red blood cells. If a person is deficient in iron, poor digestion or anemia could result.
Nutrients such as calcium, phosphorus, magnesium, sodium, potassium, iron and zinc that perform important jobs in the body building bones and teeth, transporting oxygen from the lungs to tissues and regulating metabolism.
Iodine deficiency leads to goitre, but is less common in industrialized nations due to the addition of iodine to table salt. The body needs calcium for bones and other purposes. Calcium deficiency or at least an inadequate intake of calcium can be implicated in osteoporosis and other diseases.
This mineral builds bones and teeth, and it is necessary for blood clotting. The best sources are milk and hard cheese. Others are leafy greens, nuts, and small fishes--such as sardines with bones that can be eaten.
Phosphorus works with calcium to make strong bones and teeth. A diet that furnishes enough protein and calcium also provides enough phosphorus. Other important minerals are sodium, potassium, iodine, magnesium, zinc, and copper.