Cobalt (so named from the Greek for goblin, a demon of the mines) is a greyish-white coloured metal element with the symbol Co. It was discovered among the ore veins in Cornwall in early times and called mundic by the miners. It was identified as a metal in 1733 by Brandt. Cobalt is very brittle, of a fine close grain, compact, but easily reducible to powder. It crystallizes in parallel bundles of needles. It is never found in a pure state, but usually as an oxide, or combined with arsenic or its acid, with sulphur, iron, etc.
Its ores are arranged under the following species: arsenical cobalt, of a white colour, passing to steel grey; its texture is granular, and when heated it exhales the odour of garlic; gray cobalt, a compound of cobalt, arsenic, iron, and sulphur, of a white colour, with a tinge of red; its structure is foliated, and its crystals have a cube for their primitive form; sulphide of cobalt, compact and massive in its structure; oxide of cobalt, brown or brownish black, generally friable and earthy; sulphate and arsenate of cobalt, both of a red colour, the former soluble in water. The great use of cobalt is to give a permanent blue colour to glass and enamels upon metals, porcelain, and earthenwares. Research Cobalt
Calcite is a common mineral composing such rocks as chalk and marble. It has the formulae CaCO3 and a relative hardness of 3. It effervesces vigorously with HCl. Clear specimens exhibit double refraction. Occurs as widespread sedimentary rock masses such as limestone. Crystalline metamorphosed limestones are called marbles. Argentine is a pearlylamellar variety; aphrite is foliated or chalklike; dogtooth spar, a form in acute rhombohedral or scalenohedral crystals; calc- sinter and calc-tufa are lose or porous varieties formed in caverns or wet grounds from calcareous deposits; agaric mineral is a soft, white friable variety of similar origin; stalactite and stalagmite are varieties formed from the drillings in caverns. Iceland spar is a transparent variety, exhibiting the strong double refraction of the species, and hence is called doubly refracting spar. Research Calcite
Chlorite is a mineral group whose members usually exhibit a characteristic green colour, opaque, usually friable or easily pulverized, composed of little spangles, scales, prisms, or shining small grains, and consisting of silica, alumina, magnesia, and protoxide of iron. Chlorite is distinguished from muscovite and green phlogopite by a lack of elasticity. It has a relative hardness of 3. There are four subspecies - chlorite earth, common chlorite, chlorite slate, and foliated chlorite. Research Chlorite
Fuller's earth is a kind of clay or marl, compact but friable, unctuous to the touch, and of various colours, usually with a shade of green and highly absorbent properties, composed chemically of hydrous silicate of alumina. It is useful in scouring and cleansing cloth, as it imbibes the grease and oil used in preparing wool and derives its name from being used by fullers in the cleaning and felting of cloth. It consists of silica 50 per cent, alumina 20, water 24, and small quantities of magnesia, lime, and peroxide of iron. There are very extensive beds of this earth in several counties in England. Research Fuller's Earth
Rottenstone is a light, porous, somewhat friable, siliceous rock used for polishing steel and other metals. It consists almost entirely of silica, with a small percentage of alumina and other impurities, and is derived from siliceous limestones after the removal of the calcareous matter. Research Rottenstone
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Abbreviations
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