#Grain Sizes in Sy. Resin
18 messages in this thread
A Friend of mine is searching for a block of synthetic resin with embedded soil
grains of different sizes. Its used for a quick comparison of grain sizes in
field.
Does anyone know where he can buy that in Germany or elsewhere?
Thanks
Andreas Bohleber
Hi, Andreas–
Welcome to the forum/section!
Since no one else has offered an answer, and since I have no idea, I offer
another place or two to try.
The sci.geo.geology newsgroup is accessible from CompuServe; my notes on doing
so are in SCIGEO.TXT in this forum's library.
This seems a natural for sand collectors, but the only one I know is no longer
on-line. Sand Collectors International and/or the International Society of
Sand Collectors must have people with the answers, but I lack addresses for
them in the short term. I'll try snail-mailing the fellow I know if no one
here comes up with such addresses.
–Doug
Hi, Doug!
<<This seems a natural for sand collectors>>
You mean I'm NOT the only one on the planet who collects sand?? I can use this
bit of information next time my friends tell me to "get a life, Howard!"
I've got a small, but diverse collection of sands from all over the world–
including Antarctica and Heard Island (one of those restricted access,
military-type islands in the southern Indian Ocean). It's a great hobby for
anyone with a stereo microscope, and I strongly recommend it! You can learn a
lot about sand(stone) provenance/petrology/mineralogy–not to mention
micropaleontology–from scrutinizing beach samples.
Howard
Hey Howard
Should we call you SandMan?<g>
I have looked at sand a bit and they are very interesting.
The clays that I have looked at are also interesting.
I'll never forget the first time I looked at Black Muck Clay and found that it
was 99% almost clear quartz sand.
I believe that most sand was caused by the condensation of elemental gases.
Some sands are created by the traditional grinding process as evidenced by the
coral sands around tropical islands.
The consistency of sand after being segregated by wind and water is amazingly
consistent in not only size but composition.
Please tell me what you have found in sand.
Kamron
Hi, Kamron
<<I looked at Black Muck Clay and found that it was 99% almost clear quartz
sand>>
What was the 1% that presumably gave it the appealing name "black muck"?
Some of the more interesting sands in my collection are the single-mineral
sands that occur in some areas where heavier minerals are sorted by wave or
current action into concentrated deposits. The most common of these seems to be
magnetite sands, which are nearly 100% black magnetite. I have samples from New
Zealand and Costa Rica. I also have a purple sand from a lake beach in northern
Saskatchewan, that consists of about 95% garnet.
Many sand samples from tropical beaches contain amazing varieties of
microscopic shells, including foraminifera, ostracods, tiny gastropods; and
other objects such as sponge spicules, which come in a variety of bizarre
shapes. Some of the pink sands from various beaches in the Caribbean (Bermuda,
Barbados) are colored by red forams.
Howard
Howard
There are minute traces of black quartz? and some organic material. The
image of the dark particles is transmitted through all the clear grains to make
the whole appear dark.
The magnetite and garnet sands are wonderful. I want some!
A large amount of the sands that I have inspected are of a single material and
similar in size. While that is something that we could assume was sorted by
wind and water that can accomplish the task, what is missing is segregations of
the material that was with the original sand materials. These missing
components lead me partially to the conclusion that some sands are caused by
condensing gases and the pure material becoming contacting water and
shattering.
Similar to the processes that formed the virgin gravels.
The creation of sand from the weathering of mountains just doesn't add up.
Kamron
Kamron:
<<what is missing is segregations of the material that was with the original
sand materials. These missing components…>>
What about all that mud…and all the salt in the oceans? I don't think there
is any "missing" material that needs to be explained away.
The ultimate origin of all clastic sedimentary rocks is igneous and metamorphic
rocks–granites, lavas, gneisses, etc. All these primary rocks are composed of
mixtures of minerals, some of which are less resistant to chemical and
mechanical weathering than others. For example, granite is made up of feldspars
(mostly), quartz and dark minerals such as micas. Feldspar and mica are broken
down by chemical weathering processes–mildly acidic rain water, organic
compounds–to produce clay minerals (such as kaolinite) and ions (such as
potassium and magnesium). The clay minerals are concentrated to form clays and
muds, while the ions wind up in the sea to form various salts. What's left?
Quartz! Quartz is relatively resistant to both chemical and mechanical
weathering, so ends up being concentrated as sand. The hardest and most inert
minerals in any rock are likely to be concentrated as sand under the right
conditions, including garnet (a common component of schists) and magnetite
(common in many volcanic rocks).
Howard
>> What about all that mud…and all the salt in the oceans? I don't think
there is any "missing" material that needs to be explained away.<<
OK I'll buy that the muds clays and dirts could be parts of the original
mountains that wore away for tour of the thought.
>>The ultimate origin of all clastic sedimentary rocks is igneous and
metamorphic rocks–granites, lavas, gneisses, etc.<<
If you take an original granite for example and take away all but the quartz
groups you end up with multiple colored grains as a majority of the crystals.
The individual grains are even varied in color. The whole is a wide range of
colors as well as some range in crystal size within a sample. You sort this
pile of multi size and multi colored grains by wind and water and you should
get piles of various colored grains sorted by size shape and density.
However we have deposits sorted by colors also how?
Sand deposits along the great fractures systems are present in various sizes
and colors mixed with virgin gravels of all sizes and colors. How do you
account for this mix?
Kamron
Hi, Kamron–
I expect deposits "sorted" by color come from parent rocks of a particular
color or chemical composition. If one granite mountain has all smoky quartz (I
do not know if this happens, it is an example), it will produce all smoky
sands. Some rock formations have only red garnets, some have only orange
garnets, etc.
"Llanoite" is granite from a particular part of Texas prized for its colors –
it includes blue topaz and a rather pink microcline (I think that is the pink
mineral).
Some granites may have multiple colors of quartz, but that is likely more the
exception than the rule. I expect colorless quartz most of the time from
granites.
–Doug
Senor Doug
>> "Llanoite" is granite from a particular part of Texas prized for its colors
– it includes blue topaz and a rather pink microcline (I think that is the pink
mineral).<< Wow ! Where in Texas?
>>Some granites may have multiple colors of quartz, but that is likely more
the exception than the rule. I expect colorless quartz most of the time from
granites. <<
I agree…
colorless quartz makes up a remarkable percentage of all the materials I have
looked at closely. Not a whole lot but constantly working on it. Even the
darkest granites I looked at break up into mostly clear particles. The deep
tints are thin sheets of colors (mica?) &or feldspar
between the quartz crystals and when the crystals pop apart the sheet looks
like it shatters.
I never expected mostly clear quartz until I looked myself.
Like you mentioned the giant granite batholiths that have a consist
combination of elements. This huge wide area of consistent demonstrates a
layering or stratified condition of the materials in the earth. The core of
solid metals another layer. The presence of other combinations of metals in
close proximity leads me to conclude they may be separated into single or
multiple layered groups.
As the cracks opened up to different depths and certain amounts of material
from sets of groups pours into the crack and get mixed up together then as the
cracks close back up the mixed group is injected into cracks and seams where we
find them. This is the process where so many different types of mixtures can be
found in isolated and repeated groups.
Kamron
Hi, Kamron–
>> what is missing is segregations of the material that was with the original
sand materials
You mean where is the other material that was sorted apart from the one-size
one-mineral sand? Try dirt!
Garnet, zircon, and quartz should survive better as sands than anything
ordinary because they are the hardest among rock-forming minerals. What's
missing from a sand of these is what got pulverized.
As for what is missing from a magnetite sand (it is softer), find the nearest
quartz sand deposits (and again, dirt).
As for the missing sizes of quartz, dig deeper! If it gets small enough, once
again, seek out the local dirt.
–Doug
Doug
>>You mean where is the other material that was sorted apart from the one-size
one-mineral sand? Try dirt!<<
What dirt, I never saw no dirt.<g>
You said it one-size one-mineral sand. You have a vast dune of a unique little
sand like Big Bear Dun in Michigan. Where are the larger grains of equal
volumes. There should be sets of sand groups sorted by sizes laying around in
the general area but there not.
The sand that you find along the north Texas coast is all of a certain size
regardless of the river that carried it to the coast. Big rivers and small
rivers all a similar range of size and identical makeup.
Where are the larger grains? Where are the darker grains?
If the sand came from granite the individual quartz crystals are not all
clear. Most on the contrary are stained with impurities. Normally there are
mixes of various types of grains. Very few quartz crystals in granites appear
to be this consistent color that we find in many quartz sand beds associated
with rivers.
Kamron
Hi, Kamron–
Sand dunes are liable to have moved many miles under wind action. Your
chances of finding the other size sands that were removed by sorting are
minimal. Any hope of finding the missing sizes must be in a relatively
confined area like a single river.
You assume the missing sizes will themselves be sorted – that is unwarranted.
Let a steady wind blow over a sand, and all sizes below some critical size will
be blown away if any are. There is no guarantee that mix of smaller sizes will
get sorted, or that it will not get ground to powder in whatever new home it
finds. It may get washed out to sea – if it is smaller that is easier.
Several adjacent rivers may have the same size because that is the common
crystal size in a large batholith the rivers all drain (perhaps anything
smaller just goes straight out to sea without ever stopping).
Cloudier quartz crystals are likely cloudy because they have more flaws than
clear ones from the same chemical environment. They are thus more likely to be
shattered into powder, leaving only the relatively flawless ones to form sands.
–Doug
Hello Doug
All good thoughts.
>> Several adjacent rivers may have the same size because that is the common
crystal size in a large batholith the rivers all drain (perhaps anything
smaller just goes straight out to sea without ever stopping). <<
Still should be some dark material that sorted with the sand.
>> Cloudier quartz crystals are likely cloudy because they have more flaws
than clear ones from the same chemical environment. They are thus more likely
to be shattered into powder, leaving only the relatively flawless ones to form
sands. <<
I like this too …but not all off color material would be flawed some could
be harder.
The dark clays I have looked at have are mostly clear or slight cream single
colored but varied in size with a minor portion of colored materials in them.
My experience in this is limited but I am none the less shocked by how much of
the material even in dark clays is clear. I am wondering how much this is true
with other clays. You scoped the clays much?
Kamron
Hi, Kamron–
It occurs to me that the dark material is often gone before the granite fully
breaks up. The black minerals in a granite-like rock are almost entirely black
due to iron, often in reduced (ferrous) form.
I have quite often seen granite-like rocks with a layer of crumbly rock at the
surface – unlike the obvious parent rock, there is little or no black material,
only rust-brown, while the white minerals still seem intact. You can crumble
this stuff in your hand. The black minerals (biotite, hornblende, whatever)
have evidently disintegrated as their iron content oxidized, yet the quartz has
not even finished breaking loose.
If any black minerals survive this chemical weakness, the harder quartz grains
will powder them, with help from any feldspar not yet gone to clay. In true
granite we are mostly talking biotite mica, hardness only 2; in more common
granodiorite, hornblende at hardness 5-6 may hold up longer, but not forever
against quartz at hardness 7. You will not find much hornblende in sands from
these rocks; it has colored the local dirt brown instead. Indeed, I am mildly
surprised that magnetite sands survive (hardness 5.5-6.5, with ferrous iron),
and figure they do not endure like quartz sands.
Cloudy quartz could not be detectably tougher than flawless quartz, though it
might occasionally be just as tough if the cloudiness is a chemical
discoloration rather than evidence of flaws (the only reason for quartz to be
less than ideal in hardness).
With no microscope to my name yet, I have not had a chance to view clays or
much of anything that way. Since clay minerals are mainly aluminum silicates
from weathering of feldspars (I neglected to mention this is where a lot of the
feldspars went!), colorlessness does not surprise me; a little rust in the mix
can color a lot of otherwise colorless materials.
I believe it is Mason county, TX, where llanoite is found.
–Doug
Hi, Howard–
You are clearly not the only sand collector; indeed, I am a bit peeved that
sand collectors have two international clubs while we fluorescent mineral
collectors have only the Fluorescent Mineral Society (well, the
Franklin/Ogdensburg Min. Soc. might be called another, but it is about only
some fluor. minerals and also about other F/O minerals). However, I have not
heard from any on-line since the one dropped off.
–Doug
Hi, Andreas-
I've never seen sand size scales embedded in resin, but we wellsite geologists
use plastic cards with scaled (Wentworth/phi) sand sizes for quick, accurate
size comparison. My favorite card is made by:
Canadian Stratigraphic Service Ltd.,
3613 33 Street NW,
Calgary, Alberta, Canada T2L 2A7,
phone (403) 284-1112
American Stratigraphic Company,
6280 East 39 Avenue, Denver, Colorado, 80207
phone (303) 399-2746
(note: these addresses are several years old…I know the Canadian address is
still good)
An alternative is a small (3" x 4") folder containing glued-on, graded sand
samples. One source for these is Petrocraft Products Ltd., also of Calgary,
Canada. I don't have the address at hand, but can get it if you're interested.
Howard
Hey you sand collectors,
Although I do not collect sand, my wife would kill me if I get in to one
more hobbby, a member of our Fluorescent Mineral Society does. He is the
Regional Vice President of the FMS in South Africa. As I recall he was (or is)
an officer in the International Sand Collectors Assn. You might want to
contact him:
Horst Windisch
PO Box 17273
Groenkloof, Pretoria
0027 SOUTH AFRICA
Rod