List to the episode here:
Show notes:
Music included in episode
Fold of Evening by Aazav
Iron from Stone by Damh the Bard
Here are some of the definitions we discussed and links to the quotes I used for each section.
Element:
Elements are atoms, the smallest piece that we can split matter into (except for subatomic particles and other things that we’ll leave to the physicists). Different elements have different properties. Take two different elements: iron and helium. Iron is very different than helium. You wouldn’t fill a balloon with iron any more than you would try to build a bridge out of helium. (ASU)
A solid can be made of a single element, and as we will see that is not a mineral. The elements that are known are all listed in the Periodic table. They have different properties and are defined based on the number of protons and electrons. Periodic Table
Mineral:
Minerals are materials that meet five requirements. They are:
1. naturally occurring,
2. inorganic,
3. solids,
4. with a definite chemical composition, and,
5. an ordered internal structure
(geology.com)
or from mindat.org an “informal but practical definition”
A mineral is a chemical element or compound that:
1. has a more-or-less constant composition.
2. is usually a solid with an ordered three dimensional array of ions and molecules in its crystal structure.
3. is formed by natural geologic processes and without human or other biologic intervention.
4. is not a mixture of two or more blended substances.
(mindat.org)
The ordered internal structure is also called the “Crystal Structure”
“Crystal structure is a continuous ordered arrangement of one or more elements. This is simply a fancy way of saying that minerals are composed of elements that are stacked in an orderly and neat fashion. You can think of elements as different sized marbles (except, in this case, the marbles are all very, very tiny!). Based on the relative sizes of the marbles, they can be stacked in different ways […].
A good example of a simple mineral is table salt (Yes, salt is a mineral.). The proper mineral name for table salt is halite, and a geologist will often identify it by tasting it. Salt is composed of two elements; Sodium (Na) and Chlorine (Cl). Sodium and chlorine are strongly attracted to each other and stack together into a cubic crystal structure (see figure). Individual salt (halite) crystals have a cubic shape to them, which is mimicking the way that the individual elements are stacking together. Even though the elements are much too small to be able to see with your eyes (or even most microscopes), you can tell how they are stacking together by looking at the shape of the salt crystals.”
(ASU)
“Most importantly, [a mineral is something that] has been exhaustively studied and characterized by mineralogists, declared unique in its composition and structure, and the original specimen(s) that was studied deposited for preservation in a professionally curated museum.” (mindat.org)
Resources:
MinDat
WedMineral
Mineraloid:
“A mineraloid meets almost all of the criteria of a mineral except the organized structure. Some can also lack the definite chemical composition. Minerals as we talked about are “crystalline” meaning they have an organized structure. Because mineraloids are “amorphis” they do not have an order structure. I think this is better explained with examples. Opal, obsidian, pele’s hair, and tektites are all mineraloids. Now the last few are types of natural glasses where because of the heat and the quick cooling no crystals are able to form.” (Geology.com)
There is some controversy if organic materials can also be included. Remember that part of the definition of a mineral was that it was non-organic. This means some people include things like amber and jet as a mineraloid and others don’t. Jet is a type of coal which is made from plant material like leaves and amber is from plant resin. Also there are materials that are made in the deep ocean from the “ooze” made up of tiny organisms like diatoms and radiolarians shells called diatomite and radiolarite. For our sake I think we should also consider these mineraloids since they also lack an organized structure.
So in that case a mineraloid is a solid, naturally occurring material without a defined interior structure and may or may not have a defined chemical composition, generally inorganic but some organic materials can also be included.
Anthropogenic substances:
“Anthropogenic substances are those produced by humans. They are not minerals. Crystals grown in a laboratory (or someone’s basement) or in laboratory or industrial furnace or retort are not minerals. Any crystals that are found on or in any man-made object are not a mineral.” (mindat.org)
Rocks:
“A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition and the way in which it is formed. Rocks are usually grouped into three main groups: igneous rocks, metamorphic rocks and sedimentary rocks.” (wikipedia)
“A rock is not a mineral, nor is a mineral a rock. However, the components of a rock are minerals. Most types of rock have multiple minerals, a few have only one. Single mineral rocks are termed monomineralic rock.” (mindat)
Igneous Rocks:
An igneous rock starts out purely as a melt. Everything is liquid and all the elements are there swimming around. Then it starts to nucleate minerals, some start growing before others and use up all the elements they want. It can either cool slowly and all the crystals will grow into an interlocking solid material like a granite, or can be brought to the surface and erupt and cool quicker with some small crystals and the melt freezing not having totally formed crystals. Obsidian is the extreme of this where basically no crystals have had time to form and the melt is just frozen. Of course it is a little more complicated but we can go into that another time.
Sedimentary Rocks:
Sedimentary rocks are formed when the rocks at the surface break down either physically by breaking apart into smaller pieces or chemically. These small bits can be redeposited and smoshed and get cemented together and this forms our sedimentary rocks. Generally speaking when a rock physically breaks apart you can end up with either pieces with several minerals, or a single crystal and anywhere in between.
Metamorphic Rocks:
Metamorphic rocks can be formed from either sedimentary or igneous rocks. These are rocks where the original rock is subjected to higher levels of pressure and temperature and the minerals can start to change into other minerals. This can happen to a small or large degree and rocks can also start to flow and make cool patterns. Then this smooshed and heated rock is brought back to the surface for us to marvel at. The minerals in the original rock can change their composition and/or structure at these different conditions so one rock can be turned into multiple different types depending on how much pressure and temperature it experienced. Some minerals are only formed through this process.
Crystals/Gems:
Safety information: gem society
“A crystal is a regular polyhedral form, bounded by planes, which is assumed by a chemical element or compound, under the action of its intermolecular forces, which passing, under suitable conditions, from the state of a liquid or gas to that of a solid. A crystal is characterized first by its definite internal molecular structure and second, by its external form.” (mindat)
From merriam-webster:
1. a clear, transparent mineral or glass resembling ice.
2. the transparent form of crystallized quartz.
“A crystal consists of matter that is formed from an ordered arrangement of atoms, molecules, or ions. The lattice that forms extends out in three dimensions. Because there are repeated units, crystals have recognizable structures. Large crystals display flat regions (faces) and well-defined angles. Crystals with obvious flat faces are called euhedral crystals, while those lacking defined faces are called anhedral crystals. Crystals consisting of ordered arrays of atoms that aren’t always periodic are called quasicrystals. The word “crystal” comes from the Ancient Greek word krustallos, which means both “rock crystal” and “ice.” The scientific study of crystals is called crystallography. “ (thought co)
So then what is a gem?
“A gem is a rare mineral that is prized and used in jewelry.” (differencebetween.net)
“difference between gem and crystal is that gem is a precious stone, usually of substantial monetary value or prized for its beauty or shine while crystal is (countable) a solid composed of an array of atoms or molecules possessing long-range order and arranged in a pattern which is periodic in three dimensions.” (WikiDiff)
“A gemstone is a crystalline mineral that can be cut and polished to make jewelry and other ornaments. The ancient Greeks made a distinction between precious and semiprecious gems, which is still used. Precious stones were hard, rare, and valuable. The only “precious” gemstones are diamond, ruby, sapphire, and emerald. All other quality stones are called “semiprecious,” even though they may not be any less valuable or beautiful.” (ThoughtCo)
I will be making a formatted reference post shortly as a quick guide. Let me know if you have any questions!
