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Jan 1, 750
MERCURY
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Jan 1, 1400
ZINC
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MANGANESE
The free element (metal) is not found naturally on Earth, as it is highly reactive (though once produced, it is coated in a thin layer of oxide [see passivation], which partly masks this reactivity). The free metal burns with a characteristic brilliant white light, making it a useful ingredient in flares. The metal is now mainly obtained by electrolysis of magnesium salts obtained from brine. Commercially, the chief use for the metal is as an alloying agent to make aluminium-magnesium alloys, so -
TITANIUM
Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and named by Martin Heinrich Klaproth for the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, rocks, water bodies, and soils.[2] The metal is extracted from its principal mineral ores via the Kroll process[3] or the Hunter process -
CADMIUM
Pure cadmium is a soft, silver-white metal found naturally in small quantities in air, water and soil. Cadmium does not have a definite taste or odor. Cadmium is not mined, but it is a byproduct of the smelting of other metals such as zinc, lead and copper. Cadmium is used in nickel-cadmium rechargeable batteries and for metal plating. -
Bronze Age
During the past few centuries of detailed, scientific study of the Bronze Age, it has become clear that on the whole, the use of copper or bronze was only the most stable and therefore the most diagnostic part of a cluster of features marking the period. -
TIN
Tin has been known since ancient times. We do not know who discovered it.
The Bronze Age began in about 3000 BC and tin was used in bronze, which contains roughly ninety percent copper and ten percent tin.
The addition of tin to bronze alloys improves their properties compared with pure copper: for example, bronze is harder and more easily cast than copper. -
Copper Age
The metal and its alloys have been used for thousands of years. In the Roman era, copper was principally mined on Cyprus, hence the origin of the name of the metal as сyprium (metal of Cyprus), -
Sliver
Silver has long been valued as a precious metal, and it is used to make ornaments, jewelry, high-value tableware, utensils (hence the term silverware), and currency coins. -
Gold
Gold is found in rocks and in the ground. People came to look for gold in Australia. It was called the Gold Rush. It was a hard life digging for gold. However, in Australia, it was not unusual for gold nuggets, some very large, to be found.
