Search results
Results from the WOW.Com Content Network
Moissanite (/ ˈ m ɔɪ s ə ˌ n aɪ t /) [5] is naturally occurring silicon carbide and its various crystalline polymorphs.It has the chemical formula SiC and is a rare mineral, discovered by the French chemist Henri Moissan in 1893.
In 1893, Moissan began studying fragments of a meteorite found in Meteor Crater near Diablo Canyon in Arizona. In these fragments he discovered minute quantities of a new mineral and, after extensive research, Moissan concluded that this mineral was made of silicon carbide. In 1905, this mineral was named moissanite, in his honor.
Chalcolithic Age (copper age) beginning about 7,000 years ago: copper, gold, silver, mercury. In the early Bronze Age, lead was used with antimony and arsenic. [2] The use of meteoric iron–nickel alloy has been traced as far back as 3500 BC. Iron Age, Ancient Near East (1300–600 BC), India (1200–200 BC), Europe (1200 BC – 400 AD).
A copper axe found at Prokuplje, Serbia contains the oldest securely dated evidence of copper-making, c. 5500 BC (7,500 years ago). [16] The find in June 2010 extends the known record of copper smelting by about 800 years, and suggests that copper smelting may have been invented in separate parts of Asia and Europe at that time rather than ...
Reconstruction of Ötzi's copper axe (c. 3300 BCE). The Copper Age, also called the Eneolithic or the Chalcolithic Age, has been traditionally understood as a transitional period between the Neolithic and the Bronze Age, in which a gradual introduction of the metal (native copper) took place, while stone was still the main resource utilized.
The earliest gold artifacts were discovered at the site of Wadi Qana in the Levant. [13] Silver is estimated to have been discovered in Asia Minor shortly after copper and gold. [14] There is evidence that iron was known from before 5000 BC. [15] The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in ...
‘Rare’ gold coin found in Canada may break record and reshape history, officials say. 3,700-year-old lice comb found with oldest alphabet’s first full sentence, experts say.
Gold, silver and copper were the first to be used by ancient humans. Gold and copper are both found in their 'native' state in nature, and were thus the first to be exploited as they did not need to be smelted from their ores. They could be hammered into sheets or decorative shapes.