Questions tagged [minerals]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
8
votes
2answers
1k views

What is meant by phase-change in mantle?

Phase transition usually means changing from liquid to solid phase. But in geology literature we come across transitions from one mineral to other mineral. For example olivine-spinel transition at 410 ...
2
votes
1answer
330 views

Deadly minerals

I would like to go into mineral excavation as a hobby. What deters me is the fact there are quite a few deadly minerals/ores out there. My question is how likely is it there are those deadly ores in ...
2
votes
1answer
67 views

Did we find cinnabarit?

We searched for cinnabarit in an abandoned mine (Google Maps, in Békásmegyer, Hungary). We collected these samples, but as we are not geologists, we are not sure what we found. Pictures about the ...
0
votes
1answer
596 views

The rock that gives birth to quartz sand

Thanks to one minute of the Earth we know that beach sand mother rock, besides the quartz itself, is (or was?) made of olivine, amphibole and orthoclase. I wonder, what is the name of that rock and ...
5
votes
2answers
636 views

Were all of Earth's minerals created before Earth's formation, during, or after?

I've heard that during the accretion of proto-planets that formed the earth, 60 minerals were created through the reactions of atoms and molecules in the nebula. Do these first minerals still make up ...
1
vote
0answers
591 views

Mining iron or metals in nature

Upon watching all the videos from PrimitiveTechnology on Youtube, I've decided I would try something similar. I know how to make clay and use this to make an oven. I also know how to make charcoal. ...
5
votes
1answer
132 views

Strange coating in old lime mine shaft

Near Prague,Czech Republic is old lime mine. Most of it is closed but one short transport tunnel under one hill is publicly accessible. Tunnel has profile around 2,5x2,5m and it's slightly bended and ...
1
vote
0answers
91 views

Is it ok to use biology microscope for gemological purpose?

Is it ok to use biology microscope for gemological purpose? What's the difference?
1
vote
1answer
71 views

What type of mineral is this? [closed]

My grandfather found this thing.
6
votes
1answer
864 views

Plotting a mineral stability diagram

I'm trying to figure out how to plot the stability of 4 minerals — $\ce{CaCO3}$, $\ce{CaSO4}$, $\ce{CaMg(CO3)2}$, and $\ce{CaMg3(CO3)4}$ — with axes of $\mathrm{ln}\,a_{\ce{Mg^{+2}}}$ vs $\mathrm{ln}\,...
4
votes
2answers
2k views

What are the most common minerals at the Earth's surface?

I know how to find out the first few most common minerals, and I know how to find a list of 6800 minerals that one geologist found as a microscopic grain in this one meteorite. I can't seem to find a ...
14
votes
3answers
27k views

How do geologists find ore deposits?

From my research, there is lots of information on how to extract ore, but I can't find any information on how these ore deposits are found in the first place, apart from 'looking for surface ...
4
votes
1answer
2k views

How can I normalize this chemical analysis to a mineral with 3 cations?

$\ce{FeO}$ = 70 wt% $\ce{TiO2}$ = 30 wt% The molecular weight given of $\ce{FeO}$ = 72, and the mw of $\ce{TiO2}$ = 80. The first step I did was divide each wt% by their molecular weights to get a ...
12
votes
1answer
2k views

Why do most opal deposits occur in Australia?

According to the Wikipedia page about opals, this hydrated amorphous silica based gemstone is most commonly found in Australia, with according to the page, over 90% from Australia. Opal from Coober ...
11
votes
2answers
1k views

Is it possible for a natural fluorescent mineral to glow from the sun's rays?

I have been searching certain fluorescent minerals, such as Andersonite, and all websites are saying how the mineral will glow if exposed to Ultraviolet light. Does enough ultraviolet light come ...
12
votes
5answers
24k views

Why do gold deposits form only in certain areas of the earth?

In the map above you can find that most elements are spread evenly throughout Earth's crust and that they are available all around the Earth. However, gold can only be found in certain areas of the ...
10
votes
1answer
4k views

What kind of minerals have no cleavage plane?

Why does quartz have no cleavage plane and halite does? What do I need to know about the specific mineral so that I can decide whether it has cleavage or not? I need some kind of rule.
17
votes
2answers
14k views

What determines a mineral's hardness?

Mohs Hardness Scale is basically a measurement of the hardness of a material, or more specific, a rock or mineral. But I have never been able to figure out why some minerals are harder than others.
15
votes
2answers
17k views

Why does the colour of amethyst fade if exposed to too much light?

It is well known that the purple hue that is characteristic of the amethyst quartz ($\ce{SiO2}$) will fade if the crystal is exposed to light for a prolonged period of time. What is the underlying ...
13
votes
3answers
5k views

How and where do double-terminated crystals form?

How and where do double-terminated crystals form? Most terminated crystals form by 'growing' out of a rock. Which causes one side to be flat,(or whatever the shape of the rock it 'grew' out of was ...

1
2