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#1 abbsconey

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Posted 20 April 2008 - 07:02 PM

As i'm eagerly awaiting the arrival of my 1st meteorite, i've become enthralled with the topic at hand. A few things i am wondering are:
How does one go about slicing & polishing?
Also, seeing these beauty's magnified is a must. What is a good type of microscope & mag power to use? That is w/o breaking the bank of course.

#2 Glassthrower

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Posted 20 April 2008 - 08:04 PM

Hi Todd!

A good 10x loupe is a must. 10x is of limited use on the night sky, but it works wonders on meteorites and minerals. Surplus Shed sells a cheap $6 doublet 10x loupe that works decently well. On the higher end, Nikon and B&L make superb triplet loupes that are about $100. I found a comfortable middle road with a Belomo 10x triplet loupe I got on eBay for about $30. Works great and it opens up a whole new way to appreciate meteorites - especially the ones that have been sliced open to reveal the matrix for study.

Generally speaking, with microscopes and loupes, low power is best for most general work. My stepson repossessed the microscope I had on loaner, so I am currently limited to my loupe. But when I did have the microscope, I rarely went over 100x. Also, to fully appreciate a meteorite under the microscope, a "thin section" is needed. This is a prepared slide with a super-thin slice of meteorite on it. It allows light to pass through and it will reveal much more under magnification than a more substantial chunk which won't allow light to pass. Cross-polarized studies can also be done with a loupe or microscope and this is usually what produces those spectacular color photos you see of meteorite interiors under magnification. All you need to do this is a couple of polarizer filters (like the type used on cameras), a bright light source, and a loupe/microscope.

The way I figure, any microscope is better than no microscope when it comes to meteorites. So I currently have my eye out for an inexpensive used microscope - possibly from eBay. The older Tasco models from the 1950's and 1960's were made in Japan and have fantastic optics compared to the "student" microscopes you see offered today. These older microscopes (which typically come in a wooden storage case) can often be found in superb condition for under $50.

Slicing is best done with a diamond blade or a diamond wire saw. The thinner the blade the better because it destroys less of the meteorite. A wet-saw is a must. You can even use a wet tile saw, like the type used to cut ceramic tile. But the blades are thick and it chews up a lot of meteorite in the process.

Etching is accomplished by bathing a polished surface of iron meteorite in nitric acid or nitol. The process is discussed (and shown) in a thread in this forum here :

http://www.cloudynig...5/o/all/fpart/1

Regards and clear falling skies,

MikeG

#3 abbsconey

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Posted 20 April 2008 - 09:25 PM

Thaks for the info Mike.
In reference to cutting/slicing, should you use a jewelers saw or can you use a dremel tool?
After you mentioned the older microscope, i recall still having the one my father gave me he had as a kid. Its in a wooden box. I just have to find it.

#4 Glassthrower

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Posted 20 April 2008 - 09:31 PM

Nowdays, binocular microscopes are all the rage with the meteorite crowd, but like I said, any microscope is better than no microscope.

I've never cut my own meteorites, yet, so everything I said about them is second-hand information. I have heard of people using dremel tools to cut small meteorites, but anything bigger than a pebble would require something with more cutting power I would think.

Here's a link to some rocksaws :

http://www.dadsrocks...m/trimsaw1.html

This should give a good idea of what is generally used.

#5 molniyabeer

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Posted 20 April 2008 - 11:43 PM

Having tried the dremmel tool, I can attest that for all but the smallest rocks you'll want a true saw.

#6 abbsconey

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Posted 21 April 2008 - 05:48 AM

I got to thinking about using the Dremel & i'm sure there'd be too much waste & damage. A handsaw is in order. Of course now i have to acquire a specimen large enough to warrant surgery. :smirk:

#7 abbsconey

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Posted 21 April 2008 - 08:07 PM

Another question. I've tried to register on meteoritecentral.com & it claims to have sent me an e-mail confirming, but none have appeared. I've tried this twice in the last few days. Anyone else registered, or have the same problem?

#8 The bear

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Posted 21 April 2008 - 08:13 PM

yeap it happened to me nothing came but it has me there when i try and sign up but there is not way to confirm hence no confirmation email.
doc

#9 abbsconey

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Posted 21 April 2008 - 08:16 PM

Hmmmm.... :thinking:

#10 Glassthrower

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Posted 21 April 2008 - 09:01 PM

I tried to register there a while back, several weeks ago. I never got an email either and I just figured the site was broken or something. ??

#11 meteorite

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Posted 24 April 2008 - 03:16 AM

The list administrator is Art Jones. Email him at the following email address. I am sure he can address the problems you have been having.

listhelp@meteoritecentral.com

-Walter Branch

#12 abbsconey

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Posted 28 April 2008 - 09:53 PM

Where does one go about getting the 1cm cubes you see along side meteorites in photos? I'd like to take some picks of my new additions w/them for scale.

#13 meteorite

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Posted 01 May 2008 - 07:29 PM

Hi Todd,

Various people sell them but I cannot remember who. If you like, I can do an "allcall" to the meteorite mailing list at meteoritecentral.com and post the email addresses of those who sell them here, in this thread. You could then contact them directly.

-Walter Branch

#14 abbsconey

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Posted 01 May 2008 - 07:55 PM

Thanks Walt, that'd be great. :)

#15 Glassthrower

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Posted 01 May 2008 - 10:35 PM

I've bought two scale cubes from eBay (both from the same seller) -

http://cgi.ebay.com/...em=320216904599

This listing is old, so it might be a good idea to contact the seller first.

:)



#16 alexandersdad

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Posted 02 May 2008 - 03:20 AM

Rob Wesel at http://www.nakhladog...talog/cubes.htm
is offering scale cubes at $5. Not as smart at the DMC ones but cheaper.

#17 Glassthrower

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Posted 02 May 2008 - 09:16 AM

Yeah, honestly, anything can be used to give a good scale representation. And the standard 1-cm scale cubes are very small - most people not familiar with them don't realize how small 1 cubic centimeter is. Yes, they know 1-cm is "one centimeter", but until they actually see or hold a scale cube, it isn't apparent how small it is. When I bought my first cube (I ended up losing it and bought another), I was surprised at how small it was in person. So, when I take photos for my personal collection, I tend to use the scale cube. When I take photos to sell specimens, I use the scale cube and a common object like a quarter. For bigger meteorites, I have used telescope eyepieces and cellphones for scale. The brain seems to make a quicker connection on the relative sizes of objects if all of the objects are familiar.

Part of the appeal of the black "Drake" style 1-cm-cubes is that the majority of major collectors, dealers and institutions use them for their own photos. So it's something of an aesthetic and symbolic prop as well as a useful tool for determining scale. ;)

Regards,

MikeG

PS - don't lose the cube! It's easy to drop and lose. I keep it in a gem jar when I am not using it.


#18 abbsconey

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Posted 03 May 2008 - 05:53 AM

Thanks for the links men. I realize how small a square centimeter is, but considering examples are measured by mm's i thought it best to use a scale model to represent. That said, i think i'll do the coin version until i stumble upon thme in the future. There's a gem show in late august not far from me, maybe i'll score a few there. I say a few realizing i will probably lose more than i keep.

#19 The bear

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Posted 03 May 2008 - 12:25 PM

dungeon and dragons players use cubed dice i have quite a few you can get them at book stores or order them online might be a cheaper alternative to special cubes. unless this is your aim special stuff for special stuff.
doc

#20 abbsconey

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Posted 03 May 2008 - 12:40 PM

I'm sure if you use anything common for the scale effect, it would suit. Although, i don't understand the purpose for the north,south,east, & west on the cube. Is it really necessary to know which way you're facing when photographing an example? Maybe i'm missing something.

#21 Glassthrower

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Posted 03 May 2008 - 06:16 PM

Hi Todd,

The scale cube is also used in the field by meteorite hunters. When a meteorite is found, they place a scale cube next to it with the directions on the cube aligned with the compass points. This not only gives an instant idea of size via relative scale, but it also shows the original orientation of the meteorite in-situ. Typically, the find is photographed from several angles and also shown with an active GPS readout to confirm the location. :)

There are also markings on the cube to denote top and bottom. So when the specimen is rotated for photos, the cube can be rotated to show which face is showing.

Regards,

MikeG

#22 abbsconey

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Posted 03 May 2008 - 06:49 PM

Thanks for the explanation Mike. :)


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