MINI FAQ identifying rocks, minerals and fossils using newsgroups

Using newsgroups to identify rocks, minerals or fossils. Mini FAQ V
1.2  Date  21-July-2003
Author: Nigel Whittington e-mail :
[EMAIL PROTECTED]

These guidelines are to help anyone trying to get an identification of
a rock, mineral, fossil or geological feature by submitting a query to
the sci.geo.geology newsgroup. They are not a guide to identification
of rocks, fossils or minerals (for which see the links below), but
rather a guide to the sorts of information helpful for identification.
It includes a few simple tests you can do that will help others give
you a better ID.

 A common query is 'have I got a meteorite'. This gets its own
section, below.

(1) Please do not post image files (.gif .jpg etc) to this newsgroup,
which is not a binaries group. Not only is it bad nettiquette, but
also many people are not able to view the files. Instead, post your
images up on a website (many free web hosts are available)  and post
the URL (the http://www.**** thing) to the newsgroup.

Try and include in your picture something for scale. Remember, lots of
people on the group may not know how big a dime, euro-cent or pound
coin is! If you don't include a scale  then state the size of the
object in your posting.

(2) Your local natural history museum, local geological or 'rockhound'
club or society are often able to give you advice. Universities or
colleges might have a geology or earth-sciences department (phone up
and see if anyone can help.) There are plenty of  books, from basic to
advanced in your local library, which may also be able to point you in
the direction of any local groups. You could always post to s.g.g. and
ask if anyone knows of a group in your area.

(3) Include details of where the specimen was found, don't forget that
the newsgroup readers live all over the globe, so if it found "on the
northeast coast" don't assume we know which country you mean. As well
as a geographic location try and include, if you can, a stratigraphic
location, -where in the column of rocks the specimen was- . If you
don't know this then a description of the rocks at the location it
came from is helpful.

(4) Give as full a description as you can. Don't be afraid to use
non-technical terms. It might help to read a basic book on rock and
mineral identification, or paleontology (fossils) or an online guide
(see below) before posting as this will give an idea of what
geologists look for. Look at your specimen using a handlens or
magnifier if you have one, as well as using the Mk. 1 eyeball.

Rocks and minerals  
For rocks or minerals: Crossposting to sci.geo.minerology is
appropriate.

This list contains information you can give to help the group identify
your specimen
It is far better, if you can to give a description of a freshly broken
surface, rather than a weathered one.

Colour: (I'm English, we *do* spell it this way.) 
Lustre: does it look metallic, glassy, pearly, resinous, or what? 
Texture: Does it contain crystals, grains, size? are different crystal
the same size or different? Fracture: If there is a freshly broken
surface what does the fracture look like, What shapes are any
crystals.
Density: does if feel 'heavy', 'light'? 
Hardness: can you scratch it with a fingernail, a 'copper' coin, a
penknife, a file or hardened steel chisel.
Streak: ? (No, put those clothes back on!) if you rub the sample on
the back of an old ceramic tile does it leave a coloured streak?
The acid test: Does the rock react to a weak acid by bubbling? (Toilet
descaler works fine! -use carefully-) Note-  vinegar is not usually
strong enough to cause a reaction.



Online resources: A selection

http://www.lethsd.ab.ca/mmh/grade3c/Gr3Web/rocks_miner/indentify_rocks/identify_rocks1.htm
Flow chart style, for kids.

http://www.em.gov.bc.ca/Mining/Geolsurv/Publications/InfoCirc/Ic1987-5/rockclas.htm
Decision tree for identifying common rock types -beginners

http://www.cas.umt.edu/science226/226.lab2.rocks.htm
Information on identifying rocks, undergraduate level.

http://www.acad.carleton.edu/curricular/GEOL/classes/geo110/labs/lab2.html
How to do it. Geology 110

For Fossils:

While there are only about 6000 named minerals there are tens of
thousands of genera, and hundreds of thousands of species. These range
from single celled algae to hundred tonne dinosaurs so simple
guidelines just aren't possible.
 
Crossposting of queries about fossils to sci.bio.paleontology is
appropriate.

It's a great help to know if there are any other fossils in the same
rock. If you know the age of the rock that is also very helpful. The
rock surrounding the fossil (the 'matrix') is also important so
describe this (see above).  If you have the negative mould of the
fossil (called the 'counterpart') describe this and put up an image of
it as well as the fossil itself.
There are so many different types of organism that can become fossils
that it is impossible to give a concise list of important features.
Give as good a description as you can, size *does* matter. 
Geographic and stratigraphic locations if known.

A few specific points for particular organisms:

Ammonites: Try and show, or at least describe the cross section of a
whorl
If there are squiggly lines on the side of the whorl (called 'Suture
lines) or the end of a fragment of whorl try and get an image of
these, or do a drawing and scan that.

Bivalves: Show as detailed as possible views of the dentition ( the
'teeth' that hinge the two valved together)

Post an image to a web-page and post the URL to the newsgroup (not the
image please). Close-ups help, as does a scale. Photos showing top,
bottom and both sides are useful as are close ups of detail ( indicate
what bit of the fossil if it is an extreme close up.)



Have I found a meteorite?

People are fascinated by meteorites, but in most cases what they have
found is not a meteorite, but terrestrial rock, or the result of human
activity. Unless you have found a specimen in a location (such as the
Arctic) where it cannot possibly be terrestrial then apply extreme
scepticism as to extraterrestrial origin.
Rocks commonly confused with meteorites by non-specialists include:
Haematite nodules, Foundry slag, Clinker, Marcasite nodules,
Magnetite, Human artefacts e.g. musket balls

Meteorites, some online resources:

http://epswww.unm.edu/iom/howto.htm
A good guide, includes how to test commonly mis-identified items

http://www.star-bits.com/ID.htm
Excellent guide to what is NOT a meteorite

http://www.filmright.net/Mediaright/Meteorite/Faq/FAQs/identifying.htm

http://geologynet.com/esa/space/craters/met/identify.html
Good.