![]() ![]() Gold and silver-bearing rock has to be crushed and chemically treated to get the precious element. Examples of this are found on the Coromandel Peninsula. ![]() Hot fluid can pick up gold as it flows through fractures in the Earth, leaving very tiny particles embedded in quartz veins. It suggests that tectonic plate movements allowed metal-rich fluids to come through very deep cracks and form gold deposits near the Earth’s surface. A second hypothesis has recently come to light. One idea is that the gold present in Earth’s crust and mantle came from meteors nearly 4 billion years ago when billions of tonnes of space rocks landed on Earth. However, the Earth was a molten liquid when it formed, so heavy elements like gold likely sank into the core. Scientists believe that gold dust was present when the Solar System was formed. They think that gold dust is produced when neutron stars collide, but ideas differ about why we find it in Earth’s crust and mantle. Scientists are not certain about the origin of the Earth’s gold deposits. Gold’s cosmic origins (and those closer to home) The noble metals are all found close to one another in the periodic table of elements. The noble metals resist oxidation and corrosion in humid air, which is why they are often used in coinage and jewellery. ![]() Gold is a noble metal along with silver, platinum, palladium and a few others. Imagine stretching even the chewiest piece of gum into 1 square metre! For reference, a stick of gum weighs about 1 gram. Gold is the most malleable of all metals – 1 gram of gold can be hammered into a 1 square metre sheet of gold foil. Its official chemical symbol is Au, and its atomic number is 79, which means that a gold molecule has 79 protons in its nucleus. Gold is a chemical element – a substance that contains only one type of atom. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |