Lexicon

Taken from: Peter Schmiedel & Fatiha Benyoub, Kleines Mineralienlexikon, 1994; Der grosse Brockhaus, 1979; Lexikon 2000, 1972; P. Lof, Minerals of the world, 1983; Praktische Gemmologie der Fa. Ruppenthal, 1984; Klapp, Lehrbuch des Acker- und Pflanzenbaus, 1967; Knaurs Mineralienbuch, 1968; Jander-Blasius, Einführung in das anorganisch-chemische Praktikum, 1984;


The word mineral, plural form minerals, originates from the latin word mina which stands for shaft, or the word minera signifying vein of ore. A mineral is a chemically and physically uniform natural component of the earth's solid crust, a meteorit or any other cosmic body.

Minerals alike precious stones are created by crystallization of a substance out of a solution, a melt or a vapour. During the evaporation of the solvent the containing mineral elements are enriched, thus the smallest parts, the so called crystal seeds, grow to be bigger crystalls.

This crystallization process can appear in nature in different cycles. The word cycles shall demonstrate, that once created minerals can be destroyed through natures forces and be newly crystallized and recreated again.

First we know the developping of crystal aggregates out of eruptive, so to say, volcanic activity, after the hot fieryliquid melt has solidified again. In connection with these processes there might also appear dissolved and vapourized stone formations, whose mineral ingredients could serve as starting point for crystallization.

Another form of mineral crystallization is that out of an hydrous solution, where its contents come from decayed rocks; the process of the development of the soil and that of limestone with the help of microorganisms are examples for that. This is what they call sedimentation.

Most minerals are solid and crystallized inorganic-chemical compounds; some hydrated mineral gels and their descendents, like the opal, are amorphous instead; liquid minerals are quicksilver and water.

Minerals are to be determined and described on one hand by ways of chemical, microscopic and x-ray examination, on the other by 7 external criteria as they are

  • crystal form
  • density
  • hardness after Mohs
  • cleaveability and the associated fraction
  • lustre
  • color and
  • permeability of light.

According to their chemical combination, resp. the main containing element, the classification of minerals is as follows

  • native elements
  • sulfides
  • halides
  • oxides
  • hydroxides
  • silicates
  • phosphates
  • sulfates
  • carbonates
  • tungstates
  • molybdates
  • vanadates
  • arsenates and
  • borates

Minerals mainly appear as dispersed mixtures in form of stones; these take part in the soil development and build the foundation of agricultural production, e.g. the salts of silicic acid, the so called silicates like feldspar, augit, hornblende and mica, are important sources of clay and mineral nutrients.

Minerals in small quanitities and as trace elements are life sustaining inorganic ingredients in animal and plant organisms; salts of sodium, potassium, calcium, magnesium, chlorine and phosphorus are regulating the osmotic pressure, the metabolism, the conduction of nerve stimulus and the development of teeth and bones.

Even the people of the stoneage used minerals like flintstone or nephrite for the production of tools. Minerals containing metalls , i.e. ores like iron or chalcopyrite, when appearing in deserving quantities at so called deposits, are base material for industrial production. Minerals like red chalk, cinnabar and ochre serve to produce the colors black, red and yellow-brown.

Especially the crystaline form of minerals, the precious stones, stirs excitement of people and stimulates the mind to produce decorative and ornamental objects. The first pierced flintstones and perls out of limestone and quarz where found in the older stoneage and since the antiquity we know the artistically exceptional manufactured jewellery like agate gems or bowls and basins embroidered with precious stones.

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