How is a mineral formed and what causes it to be say iron, gold, or silver? What influences this?
In: Earth Science
Answering this question is basically trying to condense a degree in chemistry into an ELI5, hang on!
Iron, gold and silver are examples of elements, not examples of minerals. In this case, all of the atoms in a piece of iron are identical (excluding contaminates or alloys.) Those three elements can occur naturally in a pure state (as a ‘mineral’) but this is generally the exception rather than the rule, at least on earth.
Minerals generally are chemical compounds, meaning they are atoms of different elements chemically bonded together.
There are about 90 elements that occur naturally but about half of them are pretty rare. Each of these elements have atoms which have a set of characteristics such as size, bonding ability and chemical reactivity that are more or less unique. Because of this, when different elements react to form compounds, the length and orientation in space of those bonds is generally unique, so the geometry of those bonds is more or less unique.
Because the geometry of the bonds in 3-dimensional space is unique, the molecules generally have a preferred way to stack together when forming a solid, so the crystal solids are also unique. It’s fairly rare that two different compounds precipitate together for form a single crystal.
Some minerals are generally ‘pure’ crystals like quartz crystals (SiO2). Other minerals are physical conglomerates of many different type of compounds, formed by physical processes such as grinding or precipitation.
This ELI5 is basically a BS degree in chemistry or geology condensed into a few hundred words. The real world is vastly more complicated, and interesting.
Platinum, uranium and other heavy elements are usually formed when two neutron stars collide.
>How is a mineral formed and what causes it to be say iron, gold, or silver? What influences this?
Pure elements like iron, silver and gold were, at some point, created from hydrogen by nuclear fusion in a star. The different types of iron and silver ore are created by oxidation, their chemical reaction with oxygen. Gold has no ore and only occurs in its pure form.
Welcome to chemistry!
Long ago people had similar questions and it was often “why is this not gold” and “can we make it gold”. This was called alchemy. Eventually we learned lots, and this was the foundation for chemistry.
Stuff is made of atoms linked up together. There are about 100ish kinds of atoms. When you have stuff made of only one kind of atom, this is an element.
Oxygen, carbon, nitrogen, silver, copper, gold, and platinum are examples of elements. You can’t make one into another at home. You can think of them as basic stuff. Elements combined make molecules. H2O is water because it has two hydrogen atoms and one oxygen atom. You can, with energy, separate them.
Elements are made with EXTREME pressure and heat. Like the kind at the core of stars. They can make elements only as heavy as iron… and then heavier of they explode in a supernova. So every bit of gold, silver, uranium, etc in the world is there because it was made in the core of a star going supernova.
Minerals form when rocks are heated enough that atoms of different elements can move around and join into different molecules. Minerals are deposited from salty water solutions on Earth’s surface and underground. Gold minerals form in hot rocks in and around volcanoes. Low sulfur, gold-bearing hydrothermal fluids form when hot rocks heat ground water. An example of these low-sulfur fluids are hot springs like those at Yellowstone National Park.
Eli5 version:
This materials already exist in the earth, mixed in with all sorts other materials. These materials are elements, the most basic type of material that cannot be made or unmade by typical chemistry you see on earth. It requires stars and nuclear fusion.
So these materials are here, and mixed in with everything else. What creates minerals of these elements, or chunks of materials is really the same processes that cause food in your kitchen to separate into different layers.
The materials all react to pressure and temperature differently, as well as presence of water and other factors.
But let’s take a simple example:. Temperature changes. A region of rich is heated enough that a lot of the material melts and mixed together. After a while the heat fades, and the area cools.
One metal will solidify forts, and settle to the bottom of the pool. Then things cool more, and the next type settles out. When it’s all over the area has settled or into layers that are more pure than normal. There is still contaminants, trapped materials, things cooled to quickly to allow things to settle and sort out.
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