Minerals

[Tetraspace]

What is a good mineral that is easily able to be tested near volcanic activity? For example magnesium? But how would you like test it? E.i. put some water on it and it will turn purple... Thanks

[kingjewel1]

Do you mean: something that will still give a positive test in high temperatures? Magnesium at those temperatures will react with steam and produce magnesium hydroxide. This is pretty insoluble (not sure how insoluble). If you tested for its pH with universal indicator it would be purple.

 

Hope that helps

[Tetraspace]

Awesome just what im looking for. Thanks dude.

[coquina]

What is a good mineral that is easily able to be tested near volcanic activity? For example magnesium? But how would you like test it? E.i. put some water on it and it will turn purple... Thanks

 

Read this:

http://volcano.und.nodak.edu/vwdocs/vwlessons/volcanic_rocks.html

and then this:

http://mineral.galleries.com/minerals/silicate/olivine/olivine.htm

 

Also:

http://www.windows.ucar.edu/tour/link=/earth/geology/min_olivene.html

Shape: Orthorhombic (usually a many-sided prism that has an overall sphere shape)

Luster: Greasy

Color: Green (but sometimes yellow or brown)

Streak: White

Hardness: 6.5-7 on Mohs Hardness Scale

Cleavage: Yes, but the crystals do not break easily along it

Fracture: Conchoidal, brittle

 

To find the color of the "streak", rub the mineral on an unglazed porcelain tile.

 

The Hardness, according to the Mohs hardness scale:

http://www.amfed.org/t_mohs.htm

Mohs Scale of Mineral Hardness

 

In 1812 the Mohs scale of mineral hardness was devised by the German mineralogist Frederich Mohs (1773-1839), who selected the ten minerals because they were common or readily available. The scale is not a linear scale, but somewhat arbitrary.

 

Hardness

Mineral

Associations and Uses

 

1

Talc Talcum powder.

2

Gypsum Plaster of paris. Gypsum is formed when seawater evaporates from the Earth’s surface.

3

Calcite Limestone and most shells contain calcite.

4

Fluorite Fluorine in fluorite prevents tooth decay.

5

Apatite When you are hungry you have a big "appetite".

6

Orthoclase Orthoclase is a feldspar, and in German, "feld" means "field".

7

Quartz

8

Topaz The November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8.

9

Corundum Sapphire and ruby are varieties of corundum. Twice as hard as topaz.

10

Diamond Used in jewelry and cutting tools. Four times as hard as corundum.

 

Hardness of some other items:

 

2.5

Fingernail

2.5–3

Gold, Silver

3

Copper penny

4-4.5

Platinum

4-5 Iron

5.5 Knife blade

6-7 Glass

6.5 Iron pyrite

7+ Hardened steel file

 

 

Since the hardness of olivine is given as 6.5 to 7, It is kinda hard to test it by hardness, but it should scratch most glass, and if you rub it with a hardened steel file, it will probably scratch it.

 

 

Hope this helps.

[Tetrahedrite]

Look for olivine

I don't quite understand what Tetraspace is asking in the question, however olivines are usually only present in appreciable amounts in eruptions of a basaltic nature. Volcanoes which are more felsic in nature (ie andesites, rhyolites) are going to have little or no olivine in them.

[coquina]

S/he asked a question under "homework help" titled "Volcanoes" and stated that s/he lives in Hawaii. We had already discussed that there is a mantle plume there, which burns a hole through the crust as the plate moves above it, and that therefore, the lavas are basaltic.

 

I had explained that basaltic rocks are "mafic" - high in iron and magnesium. When s/he asked about a specific mineral that would be fairly easy to identify, I suggested olivine. From my reading it seems to be common in basalt, and it should be fairly easy to identify.

 

I was hoping Ophiolite would put his oar in too. Although I have a lot of interest in geology I live on the Coastal plain of Virginia - there is 2000' feet of sediment between the surface and chrystalline basement, so surface rocks of any kind are downright scarce.

[Tetrahedrite]

S/he asked a question under "homework help" titled "Volcanoes" and stated that s/he lives in Hawaii. We had already discussed that there is a mantle plume there' date=' which burns a hole through the crust as the plate moves above it, and that therefore, the lavas are basaltic.

 

I had explained that basaltic rocks are "mafic" - high in iron and magnesium. When s/he asked about a specific mineral that would be fairly easy to identify, I suggested olivine. From my reading it seems to be common in basalt, and it should be fairly easy to identify.

 

I was hoping Ophiolite would put his oar in too. Although I have a lot of interest in geology I live on the Coastal plain of Virginia - there is 2000' feet of sediment between the surface and chrystalline basement, so surface rocks of any kind are downright scarce.[/quote']

Ahh...sorry, my mistake In that case olivine would be a very good indicator mineral.

 

Are you like me and find sedimentary geology boring as hell? I live in the sydney basin which comprises boring quartz sandstone up to 2Km thick, and a small quantity of carbonaceous shale.

[coquina]

I only became interested in geology due to the impact crater. (I understand Australia has several).

 

Check this USGS page:

 

http://geology.er.usgs.gov/eespteam/crater/

 

for an overview, look here:

http://woodshole.er.usgs.gov/epubs/bolide/

 

Geologists have always known this area didn't fit the norm. For example, in the forties and fifties, there was a USGS Geologist named Cedarstrom - in the days before core samples could be taken, he would sit beside a well that was being drilled and record information found in the tailings. He consistantly found old sediments mixed in with new ones and called the strata that they came from the Mattaponi, named for a local Native American tribe. However, some of his recordings were really askew - cretaceous on top of eocene for example. He knew something crazy was going on, and even suggested an impact crater, but he was fired from USGS for not keeping his records straight.

 

In the early '90's, a core well was drilled in the area, and unmistakable breccia turned up in it over 400' down. The investigators then knew they were almost certainly dealing with an impact crator. Oil companies had been exploring in the area, and Dave Powars was able to obtain the seismic studies. When they were all assembled they showed that there is absolutely a very large impact crater here.

 

If you look at the overview article, you can see pictures of the breccia in the cores.

 

It is bounded by listric faults in the surface where underlying compaction has created subsidence on the surface.

 

Here is a picture of Cornwallis's cave.

http://www.virginiagarden.com/water/cave.jpg

 

It is on the southern side of the York River. As you look at it, the left side of the picture faces east, towards the bay and the Atlantic. The right side faces west - towards the mountains.

 

This is a totally aseismic area - the strata you see in the picture is the Coquina facies of the Yorktown Formation (hence my name). It should be horizontal, or perhaps dipped slightly seaward. Can you see that there is a very significant dip to the west?

 

When you look at this on a topo CD so that you can exaggerate the elevation by 8x and rotate the picture, you can see that there is a huge block that fell into a creek just a mile or so to the west. It is part of the listric fault system that bounds the crater.

 

Oh yeah - after Dave Powars and Scott Bruce determined for sure that the crater was there, they tracked down Cedarstrom. He was 93 and in a nursing home. But they were able to get across to him that he was right all those years ago, and that there was a clear reason for the subsurface disconformities.

[Tetrahedrite]

Yes, we do have lots of impact craters, especially in the ancient Yilgarn Craton in Western Australia. I actually spent three months over the summer at the Australian National University (ANU) studying the Murchison Meteorite that fell in Victoria. I was involved in separating each of the mineral components in the meteorite so that they could be dated by isotope methods on a machine called a SHRIMP. Lots and lots of very strange mineral phases in that thing!!!!

[coquina]

is there anything online about it?

[Tetrahedrite]

is there anything online about it?

Heres an overview of the meteorite:

http://www.ast.cam.ac.uk/AAO/local/www/jab/astrobiology/murchison.html

There is mountains of stuff on the net if your interested.

 

Here is an overview of how the SHRIMP works:

http://wwwrses.anu.edu.au/gig/Probe/SHRIMP.html

[coquina]

I've bookmarked them and put them in my "Impact" folder.

[Tetraspace]

Ok! First off I'm a "he". And I'm asking to find out minerals that can be identified through expirementing that can be found in lava and rock formations near volcanoes. I guess thats what confused people. Theres like an iron test in which you can test the earth's magnetic feild through magnets.

[Tetrahedrite]

Ok! First off I'm a "he". And I'm asking to find out minerals that can be identified through expirementing that can be found in lava and rock formations near volcanoes. I guess thats what confused people. Theres like an iron test in which you can test the earth's magnetic feild through magnets.

Olivine is one of those minerals, what do you mean by "test", a physical test, a chemical test, a diffraction test?

[Tetraspace]

Chemical test as I stated before.

[coquina]

I still think olivine is your best bets. Here is how you test for minerals:

http://www.easternct.edu/personal/faculty/hyattj/learntools/mineraltest/

 

You work your way down the flow chart to eliminate the minerals that are obviously not what your seeking.

 

Here is are google images of Olivine (with a few stray people thrown in who happen to have that name.)

 

http://images.google.com/images?q=olivine&hl=en&lr=&start=20&sa=N

 

Olivine is varying shades of green - from very light to very dark.

 

Hah! I just found that Hawaii has a greensand beach made entirely of Olivine - are you on the "Big Island"?

http://www.sease.com/regina/hawaiibeaches.html

 

a close up of olivine sand:

http://www.fotosearch.com/CPH340/390023/

 

At any rate, the mineral olivine should be fairly easy for you to find, it originates deep with in the earth and comes to the surface with the lava.

[Tetraspace]

Awesome Thanks Everyone!

[Guest someguy]

perhaps im posting in the wrong area but ... Bismuth-83 is the basic element for Bismuth. I am wondering what progression method would take this to Bismuth-209 or if the transmutation method works like this. Befor complex explinations come out .. can bismuth-83 be altered to 109-Bu? If so would it be simply by bombarding 83-Bu with neutrons?

[budullewraagh]

eh, bismuth 83 would be severely neutron-deprived...

 

bismuth is bi, just so you know.

209 bismuth is the only kind you'll find naturally. i wouldn't suggest transmutating bismuth:\

 

210 astatine, anyone?

[Tetrahedrite]

I think you've got the atomic number mixed up with the mass number. Bismuth (Bi) has an atomic number of 83, which means it has 83 protons. All naturally occurring Bi has a mass number of 209, meaning it has 126 neutrons.

 

210 astatine, anyone?

 

mmmmmm........astatine........very tasty!

[jdurg]

I think you've got the atomic number mixed up with the mass number. Bismuth (Bi) has an atomic number of 83' date=' which means it has 83 protons. All naturally occurring Bi has a mass number of 209, meaning it has 126 neutrons.

 

 

 

mmmmmm........astatine........very tasty! [/quote']

 

Mmmm...... tastes like cancer!

 

Although, the element only lasts for a few hours so I'm not sure exactly how well it would be absorbed into the body. I actually think that I-129 would be far worse than At since I-129 has a pretty long half-life and can be readily absorbed into your thyroid. While At would chemically behave like Iodine, it decays via electron capture into polonium which will decay with alpha particles. So really, when thinking about the radiological/chemical toxicity of At you should just look at polonium. So again, I don't think that At would be nearly as dangerous in terms of cancer as I-129 would be.

[Guest someguy]

wow ... Thanks for the simple correction. Yes i had it mixed up and it baffled me. O.Kay now to build an elaborate neutron fission chamber from egg cartons and pop sicle sticks ..

 

Astatine-210 I have 5 ounces to sell

[Guest someguy]

Ok on to Q#2 ... Do elements decay in mass as in thorium-232 decays into radium-228 or does it decay in elements as in Lead-210 decays into Bismuth-210 ... witch is correct?? I get so much mixed information online .. gleeming and compiling this information can be daunting. Perhaps ill just have to post it on the web and give link to it.

[jdurg]

Both are correct. It all depends on the type of decay they use. If they emit an alpha particle (Which is a helium nucleus), their atomic number goes down by 2 and their atomic mass goes down by 4. So when Th-232 decays into Ra-228, it does so via alpha emission. If an atom decays by beta emission, it does so by releasing an electron as a neutron decays into a proton and an electron. The mass will stay the same, but the atomic number will go up by one. When Pb-210 decays, it decays into Bi-210 via beta-decay.

 

If an atom undergoes Electron Capture, it would be the same as beta decay but in the opposite direction. The nucleus would take an electron and combine it with a proton to form a neutron. Therefore it's atomic number would go down by one, but its mass would stay the same.

 

There are many different ways that an atom can radioactively "mutate" so it's a good idea to study up on that in any general chemistry/physics book you have.

[budullewraagh]

just a note: atoms can undergo positron capture as well