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#mineralmonday: tiptopite

#mineralmonday: tiptopite

#mineralmonday: your weekly* dose of obscure mineralogy, every Monday** [*not guaranteed; **or possibly Tuesday-Sunday]

tiptopite. Source: wikimedia.org.

What is it? Tiptopite: K2Na1.5Ca0.5Li3Be6(PO4)6(OH)2•(H2O)

What’s it made of?  Take a deep breath and recite after me: potassium, sodium, calcium, lithium, beryllium, phosphorus, oxygen and water (H2O).

Is it pretty? Yes, it’s a beautiful fibrous mineral. You wouldn’t put it on jewelry though, or even in your pocket, or you’ll end up with needles and dust.

Wikipedia defines ‘tip top’ as ‘a slang phrase which means of the highest order or excellent’. Is this true for this mineral? Not really, it doesn’t have any real use (we are more interested in the minerals that it is associated with, like beryl), is only found in one place (the ‘Tip Top’ mine in South Dakota), and only in some isolated areas in that mine. This mine was opened during world war 2 for strategic reasons, but then shut down again in the 1950s.

Beryllium metal. Not exactly a silver lining, but a shiny grey lining… source: wikimedia.org

Strategic mining you say? Presumably this was for mining dragon glass? Or maybe I’m mixing up my wars. Yes you are thinking of an earlier war. Dragons and white walkers were long extinct by the 1950s. This particular mine was for beryllium (the Be in the formula).

That sounds berylliant. What’s it for? Nothing fun, unfortunately. Beryllium has a useful property of being a neutron emitter and an alpha particle absorber. This makes it really useful as part of the triggering device of thermonuclear weapons. It also makes beryllium quite difficult to buy…

Is there a silver lining? Nope! Beryllium even has a couple of conditions named after it: berylliosis and acute beryllium poisoning. Luckily it’s hardly ever used these days, and the risks are well known.

It seems calling it ‘tip top’ was a little optimistic…

Do you have a favourite obscure mineral? Want to write about it? Contact us and give it a go!

#mineralmonday : sengierite

#mineralmonday : sengierite

#mineralmonday: your weekly* dose of obscure mineralogy, every Monday** [*not guaranteed; **or possibly Tuesday-Sunday]

What is it? Sengierite: Cu2(UO2)2V2O8.6(H2O)

What’s it made of? A few useful metals – copper (Cu), vanadium (V), uranium (U), plus oxygen (O) and water (H2O).

So by ‘useful’ you mean ‘radioactive’? Pretty much. The main reason people have been interested in this kind of mineral is the (very radioactive) uranium, which is important for nuclear power and military uses. The copper (not radioactive) is also useful though – this is a secondary mineral that is often found in mines where copper and uranium are extracted together.

Sengierite, from Leon Hupperichs via wikimedia.org

Secondary mineral? Like second class? That seems harsh. Basically, primary minerals are the ones that form when the rock is forming in the first place, so if the rock is crystallising from a liquid or magma, the minerals that form at that point are primary. If this rock then gets weathered, or maybe some water passes through it, new minerals can sometimes form – these are the secondary minerals.

I see, so it’s more like an caterpillar becoming a beautiful butterfly? Something like that. These secondary minerals are often hydrous, meaning they have water explicitly in their structure. That doesn’t mean the mineral is just wet, but rather there is a specific place for the water in the lattice of atoms. You can see this is the case for sengierite because of the 6(H2O) at the end of the formula.

So is it pretty? Absolutely. This one is a beautiful bottle green to apple green colour. It also has what we call a vitreous to adamantine lustre (lustre describes how light interacts with the mineral – vitreous is kind of like glass, adamantine is like a diamond). Probably best to avoid radioactive crystals for use in jewelery though…

Do you have a favourite obscure mineral? Want to write about it? Contact us and give it a go!

#mineralmonday : lithiophilite

#mineralmonday : lithiophilite

What is it? Lithiophilite, LiMnPO4

What’s it made of? Lithium (Li), manganese (Mn), phosphorus (P) and oxygen (O). The PO4 at the end of the formula makes this a phosphate mineral (phosphorus + oxygen = phosphate).

Lithiophilite crystals (the crystals that look blackish). From Rob Lavinsky, via wikimedia.org

What’s it’s structure? The way the different atoms are arranged in lithiophilite is described as orthorhombic, which means the crystal is built of lots of tiny cuboid-shaped atomic meshes (we call these individual building blocks unit cells). The mineral olivine, which makes up most of the top 440 km of the Earth, is also orthorhombic (shout out to olivine-my favourite mineral-which unfortunately is far too common for #mineralmonday).

Is it useful? Not directly. It’s far too rare to mine for lithium, the useful part of the mineral. But, if we swap out the manganese (Mn) for iron (Fe), we get another mineral called triphylite (LiFePO4), which can be grown in the lab, and is a battery material with some potential applications in electric cars and bikes.

How can a crystal be a battery? A battery is basically just a material that can provide a flow of electrons. This means that something in the battery needs to oxidise (oxidation means loss of electrons, and a gain of positive charge). The iron in the LiFePO4 can oxidise, similar to how pieces of iron will rust (oxidise) over time. It’s basically the lithium, which can move around in, and out of, the mineral, that makes this possible.

MG electric concept car, powered by a LiFePO4 battery. From jwhite65 via wikimedia.org

What is it named after? It’s a mineral that really really likes lithium, so I guess we could describe it as a lithiophile (filos, filia etc. being Greek for friend). So it’s a friend of lithium, which is convenient because it’s made of it. Just to keep things confusing, we also have the word ‘lithophile‘ in geology, which more or less means an element that concentrates in the rocks we find on the Earth’s surface (lithos = stone, in Greek again). And to round it off, the element lithium was also named after lithos, because it was originally found in rocks.

It seems like they could have used another word. But at least lithium and lithiophilite were both discovered in Greece, right? That would make sense… But no, lithium was discovered in Sweden and lithiophilite in the USA. But, they were both found in the 1800s before thesaurus.com, so let’s not be judgemental…

Do you have a favourite obscure mineral? Want to write about it? Contact us and give it a go!

#mineralmonday: lazurite

#mineralmonday: lazurite

#mineralmonday: your weekly* dose of obscure mineralogy, every Monday** [*not guaranteed; **or possibly Tuesday-Sunday]

What is it? Lazurite. Take a deep breath, the formula is Na3CaAl3Si3O12S.

 

Lazurite, from Didier Descouens via wikimedia.org

That’s a lot of elements to digest, what does it mean? Well, the aluminium (Al) and silicon (Si) form tetrahedra (4-faced 3D triangular shapes), with oxygen (O) on the points. These are arranged in rings with the sodium (Na) and calcium (Ca), with the sulphur (S) sitting in the middle. This kind of structure is called a cyclosilicate, because of the cyclical (ring shaped) arrangment.

 

OK now I’m bored. Is it pretty? Not just pretty – but pretty on a biblical scale. Lazurite is what makes lapis lazuli blue – this has been a semi precious stone for thousands of years. It’s basically lazurite with a couple of other minerals (we’ll get there another day). Here is a shout out from the Old Testament (Exodus): “Under his feet there seemed to be a surface of brilliant blue lapis lazuli, as clear as the sky itself“.

Alright I’m sold, where can I get some for under my own feet? The main worldwide source of lapis lazuli, and hence lazurite, is a mining district in northern Afghanistan. It’s been mined through the times of the Greek, Roman, Mesopotamian and Egyptian empires. As well as being used for carvings, jewelery and apparently flooring, ground up lapis lazuli / lazurite was used for making the colour ultramarine, widely used by painters in the Renaissance.

Girl with a Pearl Earring, aka Girl with a Lazurite Blue Headscarf, made from natural ultramarine.

If more minerals were blue then geology would be way more interesting, right? Probably. There are only so many ways we can describe the colours grey and brown when looking at rocks. The colour comes from the sulphur, but exactly how the sulphur relates to the colour is still apparently up for some debate.

And who or what is lazurite named after? Simply, named for the colour blue. In Persian, this is lāzhward, which was originally the name of the place where the blue lapis lazuli stone was mined, which then ended up being used to describe the colour itself.

So the mineral was named after the colour, which was named after the town, which was named after the stone. I’m confused. Me too. It’s like time travel movies. Don’t think about it too much.

Do you have a favourite obscure mineral? Want to write about it? Contact us and give it a go!