Flatirons Facets

Published by The Flatirons Mineral Club

Volume 46, No. 1 January 2004

Flatirons Facets

P. O. Box 3331

Boulder CO 80307-3331

Flatirons Facets is published monthly by The Flatirons Mineral Club. The deadline for submission of articles to Flatirons Facets is the 20th of each month. Permission is granted for reprint if credit is given to the publication and author unless specifically restricted.

The Flatirons Mineral Club is a non-profit organization, established March 9, 1957, and dedicated to developing and maintaining interest in all aspects of earth science and associated hobbies. The club meets the second Thursday of each month at 7 p.m. We meet at The Senior Center, 9th and Arapahoe Avenue, Boulder, CO. Guests and visitors are welcome. Membership dues are $15.00 per year (beginning October of each calendar year). People interested in membership can contact the club either by writing to the above address or by attending one of the meetings.

Deadline for the February Facets is January 20.

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President's Corner

Dennis Gertenbach

We ended 2003 with a fun holiday party and gift exchange. Everyone had a good time trading gifts and eating goodies.

I am pleased to announce that we have filled the open officer positions. Your officers have promised great monthly meeting programs, a wide variety of field trips, and a show next November that will be even better than this year. Thanks to all of our club's volunteers. If you are interested in helping the club this year, please let me know. The more help we get, the better club we will have.

Be sure to check the calendar for upcoming meetings, field trips, and other rockhound activities. I hope to see you at January's meeting. The Board meeting, normally scheduled for Jan 5, may be postponed to Jan 12, due to a conflict with the WIPS meeting. Check with me or another club officer for the date and time.

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January Club Meeting
 

For our club meeting on January 8, the program will be a presentation by Dennis Gertenbach on Fossil Preparation. See the related article elsewhere in this newsletter, complete with references, so you can do your homework before Dennis' talk! Also, if you have examples of well-prepared fossils, or perhaps instructive examples of mistakes you have made preparing fossils, bring them to the meeting for others to enjoy and learn from.

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Denver Gem and Mineral Show Mini Report
Judy Knoshaug, Secretary pro tem 

November 4, 2003

As all club members should know, the Greater Denver Area Gem and Mineral Council is the sponsoring organization for the Denver Gem and Mineral Show. The Council is a non-profit organization under Section 501(c)(4) of the Internal Revenue Code. The financial books for the 2003 Show have been completed and disclose that the show had a "profit" of $27,487. This money will be turned over to the Council to be used as grants or gifts to further the purposes of the Council. The stated purpose of the Council is to promote exhibition, exploration, and education in the earth sciences; for the discovery, development and preservation of minerals and mineral deposits; and for the advancement, encouragement, and utilization of the principles of art and craftsmanship as applied to gems and minerals.

 
In addition, proceeds from the sale of grab bags at the show, in the amount of $3,663, have been forwarded to the 
Colorado School of Mines to provide a scholarship to a geology student.
 

Thank you and congratulations to your club for your participation in the show. Your efforts and dedication generated these moneys, which will be used for many worthwhile endeavors in the earth sciences. Many people will be grateful.

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Mineral Resources of Central Colorado
By James A. Cappa (From CGS Rock Talk Vol 6, No 3 (2003))
 
Central Colorado has an abundance and variety of mineral resources, ranging from gold and 
silver to oil shale and coal.
 
Precious and base metals: Within this region, several important mining districts have produced 
both precious and base metals. Ore deposits in these districts are generally hosted by 
carbonate rocks of Late Paleozoic age, mostly the Leadville Limestone. Laramide-age, (75-35 
million [M] years) porphyritic igneous rocks are important in localizing these mineral deposits. 
These great mining camps are no longer productive. The last mine to operate, the Black Cloud 
Mine in the Leadville district, closed in 1999. The Leadville district produced approximately 3.3 M
ounces (ozs) of gold, 265 M ozs of silver, 2.354 M pounds (lbs) of lead, 1,936 M lbs of zinc, and 
110 M lbs of copper. Other nearby mining districts include the Aspen district with a production 
of 101 M ozs of silver; and the Gilman district with a production of 68 M ozs of silver, 1,905 M 
lbs of lead, and 323 M lbs of zinc.
 
Molybdenum: The huge, world-class Climax Mine is now on a standby basis. The Henderson 
Mine of Clear Creek County remains as Colorado's sole molybdenum producer. These two 
deposits are hosted by rhyolite porphyry intrusive complexes. Through its life, the Climax Mine 
produced about a million tons of elemental molybdenum with a "year-mined" value of $4 billion.
 
Oil and gas: The Piceance Basin covers much of central Colorado. It contains several important 
oil and gas fields including the Rangely field, which has produced 865 million barrels of oil and 
770 billion cubic feet of gas in its long life. Today, the Piceance Basin is a major natural gas 
producing area with several fields producing from Cretaceous and Tertiary age rocks. There are 
about 480 billion barrels of oil in the shale of the Tertiary Green River formation of the Piceance 
Basin. Shell Oil Co. is conducting research on in-situ recovery of oil from these oil shales.
 
Coal: There are several coalfields in the central Colorado area. The Grand Hogback Coal Field 
near Glenwood Springs produced 4 million short tons of bituminous coal; the Carbondale Coal 
Field produced 31 million short tons of anthracite and high-volatile bituminous coal. None of 
these mines are active.
 
Industrial and other minerals: There are several other important mineral resources that are 
produced in central Colorado. Gypsum is mined from the Pennsylvanian age Eagle Valley 
Evaporite near the town of Gypsum. The mine produces about 500,000 tons of gypsum a year, 
which mostly goes into wallboard fabrication. The Yule Marble Quarry near Marble produces 
outstanding white marble dimension stone. Yule marble, with its high quality and purity has 
been used for several of the nation's important monuments including the Tomb of the Unknowns 
at Arlington National Cemetery, and the Lincoln Memorial in Washington D.C. Beautiful 
specimens of gem-quality rhodochrosite, the new Colorado state mineral, are produced from 
fracture zones at the Sweet Home Mine near Alma.

[Jim Cappa is the chief mineral fuel geologist at Colorado Geological Survey.]

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Notes From Down Under
John & Jeanne Hurst
 
Outback Dictionary: 
Gibber-probably what we would call a nodule that has been weathered out of the host rock.
 
Fairy Floss-what we refer to as cotton candy.
 
A nice surprise! We brought back a small gibber, make that a thunder egg that comes from Mt. Hay in Australia. 
Under short wave U-V, it lights up a bright green. We discovered its fluorescence for the first time on Dec. 24, 
just in time for Christmas. Last month we mentioned that the Harts Range Zircon fluoresces golden yellow, but the 
Masons in Alice Springs gave us five zircons that fluoresce a bluish white. Aren't all those fluorescent rocks fun?
 

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Membership Notes
Melinda Thompson
 
Flatirons Mineral Club thanks the following members for paying their 2004 dues. A list of current 
members is in the January Facets. If your name is not on this list, there will be a red mark next 
to your address on this newsletter, and this will be your final FMC newsletter.
 
If your name is not on the list and you think that it should be, please contact the Treasurer, 
Gerry Naugle.
 
Announcement: Starting February 1, 2004 Trick Runions will be our new Membership
Chairperson.
 

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Upcoming Events, Nearby & Elsewhere

Jan. 9-11 (Fri-Sun), Denver Gem and Mineral Guild Jewelry Gem & Mineral Show, Lakeside Center, I-70 at Harlan. Lapidary Supplies, Crystals and Fossils, Unique Jewelry, Gem and Mineral Dealers, Gem cutting demonstrations. Swap Area. Free admission. Grab bag sales-proceeds applied to scholarship at Colorado School of Mines. Fri. 10am to 9pm., Sat. 10am to 6pm., Sun. 11am to 5 pm.

Feb 12-15 (Thu-Sun). The 50th Annual Tucson Gem and Mineral Show, Tucson

Convention Center, Downtown. 50th Anniversary Gold Show.This year GOLD will be

the featured species; the exhibits will be spectacular. If there is any chance that you can arrange a trip to see the world-famous Tucson Show, this will be the year not to miss!

 
April 23-25 (Fri-Sun). Colorado Mineral & Fossil Show-Spring, Holiday Inn-Denver Central, 4849 Bannock & across 
the street, Best Western-Central Denver, 200 W 48th Ave. FREE ADMISSION, FREE PARKING. Minerals, Fossils, 
Meteorites, Gems, Beads. National and International dealers. Fri & Sat 10am - 7pm, Sun 10am - 5pm.
 

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New In The Library
Dennis Gertenbach

Thanks to a donation by Richard Smith, the club's library has a new book, Fossils of All

Ages by Jean-Claude Fischer and Yvette Gayrard-Valy. The book explains how fossils are formed, what they tell us of the earth's history, and just the beauty of fossils. With 150 beautiful photographs of invertebrates, leaves and vertebrates, this book provides the reader with a better understanding of our ancient world.

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Fossil Preparation
By Marc Behrendt (Source: Rock Pickings, Eastern Indiana Gem & Geological Society, Richmond IN, July 2003 via Quarry Quips, 
December 2003)
 
You have been collecting really great fossils all day; you get home, set the box on a chair and 
spread your treasure onto the kitchen table to look at it closer. It's pretty neat stuff, but wouldn't 
it look better if all that mud and rock still stuck to it were gone?
 
Fossil preparation or cleaning can be done in the home or in a fancy lab. Sometimes all it takes 
is a toothbrush and water. If the fossil is sturdy, like coral and many brachiopods, this method 
will remove all the mud and loose matrix. However, if your fossil has any cracks in it, if it is 
fragile, or if it sits on soft shale, do not try to brush it off with water. Fossils like trilobites, bones 
and fragile brachiopods will dissolve or fragment and leave you with an empty rock and 
memories. To make something fragile look better, you need a different method to clean your 
specimen.
 
If you have access to the right equipment, you are in good shape. Or you could send your 
specimen to a fossil preparation lab. Let's assume you have a complete trilobite and would like it 
cleaned. Part of it is buried in the rock and part is exposed but covered with a thin layer of shale.
 
The first step is to stabilize the specimen. When the rock dried after it was dug up, all the water 
evaporated, leaving countless microscopic cracks both in the rock and in the fossil. Apply super-
thin super glue under a microscope by dipping the tip of a pin into a drop, and then touch the 
pinpoint to a crack, which sucks up the glue instantly. The glue hardens, filling in the crack and 
holding everything together. If too much glue is used, such as with a single regular drop, then 
the glue will have to be cleaned away before the matrix can be cleaned from the trilobite.
 
Now the fun begins! To expose the buried portion of the trilobite, pneumatic hammers will be 
used. These are just like the loud jackhammers road workers use to dig holes through the 
roads; except fossil preparing hammers are so small they must be used under a microscope. 
Ever so carefully the hammer's pounding chips away tiny fragments of the matrix hiding the 
trilobite. Usually the matrix touching the trilobite shell pops right off after most of the upper 
matrix is removed. Great care is taken not to touch the trilobite with the hammer, because a 
hole in the fossil is not pretty.
 
Before micro-air hammers were used, fossils were exposed using small steel picks like dentists 
use (this process is still used in many labs today). The method works very well, as you can see 
in any older museum collection, but it takes a long, long time to accomplish what an air hammer 
can do in a short time!
 
OK, the trilobite has been totally exposed, but is still covered by a thin layer of shale. It is time 
to pull out the micro sandblaster. Also known as air abrasive machines, these instruments, 
using high air pressure, shoot a tiny regulated amount of powder through a hose and nozzle onto 
the fossil, eroding the soft rock away while leaving the harder trilobite's shell intact.
 
Depending on the type of rock and the hardness of the fossil, the air pressure, the amount and 
type of powder and the size of the nozzle can be changed to meet the situation. Imagine this - 
you have big rock and you want to break it in half. You first choose your hammer. Will it be 
small and delicate or big and heavy? Should it be made of rubber or metal? Then, do you swing 
it really hard, or gently tap the rock? Too much hammer or too much swing and your rock is 
dust. Too little hammer or tiny taps may crack the rock in a day or two. The right hammer with 
the right swing will cause the right impact to break the rock in a controlled manner in a short 
time.
 
The same concept is used with the air abrasive machine. With experience or careful 
experimentation, the air pressure and powder flow are adjusted to remove the matrix from the 
fossil without "burning" the trilobite's shell away with the rock. All the work is done under a 
microscope under the watchful eye of the preparatory, who is alert for new or previously 
unnoticed cracks in the shell that will need to be stabilized.
 
Although it is important to clean the entire trilobite carefully, the eyes need special attention. 
Many kinds of trilobites have the lenses still in the eyes, and these are very fragile. With delicate 
and precise micro sandblasting, the entire eye is cleaned so each lens is perfectly exposed 
without being damaged!
 
Finally, the rock itself is spruced up. All the chisel marks from the hammers are ground away 
using either a combination of air hammer and air abrasive, or with a grinder like a dremel tool. 
The matrix is shaped into the way it best displays the trilobite. Occasionally, new fossils are 
discovered under the matrix during this step. These are cleaned up and make nice surprise 
additions for the piece.
 
When it's all done, sit back and admire your trilobite. It's no longer gray and covered with rock - 
it is a beautiful black or brown color, looking like it will crawl off the rock any moment.
 
There are many other techniques available for preparing fossils. Several books are available 
which describe different methods. Three of the many are:
 
Paleotechniques, edited by Rodney M. Feldmann, Ralph E. Chapman and Joseph Hannibal.
Published by the Paleontological Society at the Department of Geological Sciences,The 
University of Tennessee, Knoxville, TN 37996
 
Handbook of Paleo-preparation Techniques by Howard H. Converse Jr. Published by Florida 
Museum of Natural History, University of Florida, Gainesville, FL 32611
 
Fossil Preparation Manual by Tom Whiteley and Gerry Kloc. Published by the authors, 1995
 
[Mr. Behrendt specializes in Trilobites, Gastropods, Echnioderms, Brachiopods and his services include: 
fossil cleaning and preparation, fossil, collecting, writing fossil related articles, speaking on fossil related topics. 
He can be reached at 421 S Columbus St., Somerset OH 43783 (740)743-2818 or e-mail Fossil Prep@aol.com]
 

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Where Did Christopher Columbus Go Wrong?
By Ernest Barnhart (From Rock Buster News. 3/01 Via Strata Gem, 1/03 via Rocky Mountain
Federation News,10/03)
 
Columbus has been described as a man who didn't know where he was going, didn't know 
where he had been, did it several more times, and all on borrowed money. However, he is the 
only foreigner honored with a legal holiday in the United States - unless you live in some parts of 
California where you are asked to observe "Indigenous Americans Day" instead.
 
The idea that the world is round was widely accepted by the time of Columbus. The main 
dissent was from the church, which held that the earth was a flat disc covered with a canopy, 
probably to provide a physical manifestation of heaven.
 
The spherical earth theory was proposed by several Greeks, the first of which was Aristotle (384-
322 BC), who observed the shadow on the moon during an eclipse and concluded that this could 
only be caused by a round object.
 
The first who actually sought to prove this theory was Eratosthenes (circa 276-196). Born in 
Libya, he was the chief of the library at Alexandria, Egypt. This library was the repository of 
more than 100,000 scrolls containing the world's collective knowledge.
 
Eratosthenes heard of a well in what is now Aswan where the sun's reflection could be seen in 
the water of the well on June 21, the longest day of the year. He surmised that the sun was 
directly above the earth at that moment. He knew that this location was directly south of 
Alexandria and by measuring the shadow of an obelisk in Alexandria at the same time there was 
no shadow at the well, he computed the length of the two sides of a triangle, the length of the 
shadow and the height of the obelisk. He figured the angle of the triangle, which was 7 - 12 
inches, approximately equal to one fiftieth of a circle's 360°.
 
He still needed one more measurement. The Greek standard of measurement was the stadia 
(based on the size of a Greek race course). Standard camel performance was to cover 100 
stadia per day, and since it took a camel 50 days to make the trip between his two points, he 
calculated the distance to be 5000 stadia multiplied by 50 and come up with a figure of 250,000 
stadia for the earth's circumference. Translated to modern measurements, his earth measured 
25,000 miles, amazingly close to the actual distance at the poIes of 24,860 miles. His scientific 
apparatus for this experiment consisted of something to measure the length of a shadow.
 
Unfortunately, some people cannot leave well enough alone. Sometime later, another Greek 
scholar named Strabo, for some unknown reason, reduced Eratosthenes figure from 25,000 to 
18,000 miles. By Columbus' time the original calculation had been overlooked and it was this 
latter figure that Columbus relied on for his voyage.
 
Columbus knew the approximate distance from Europe to Japan, west to east, thanks to Marco 
Polo's journeys to the Far East. If his calculations of the earth's circumference of 18,000 miles 
had been correct, he would probably have been justified in assuming he had reached the Orient. 
A Greek scholar, 1700 years before Columbus' voyage had it right, and if Columbus had had the 
correct information, he may have realized he was 7,000 miles short of his objective. 

Reference:

Don't Know Much About Geography by Kenneth C. Davis

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Minutes of the Board Meeting, December 10, 2003
Emily Epstein, Secretary
 
Present: Alex Cook, Emily Epstein, Dennis Gertenbach, Ray Gilbert, Ray Horton, Charlotte 
Morrison, Gerry Naugle, Terry O'Donnell, Paul Ralston, Richard Smith.
 
Dennis Gertenbach said that since we have a new board, we need a new board chair. Alex Cook 
asked why the president isn't chairman of the board--none of the other organizations he belongs 
to has both. Dennis offered to consult the bylaws and see if it might be possible to combine the 
two offices. Meanwhile, the board voted to elect Dennis to both positions.
 
Dennis announced that the show committee met and recommended having the show next year 
at the Elks Lodge. They have asked the Elks for the 3rd weekend of November, and if that is not 
available, the 2nd weekend. Alex Cook has volunteered to serve as Show Chair, and John Hurst 
will serve as Dealer Chair. The board voted to accept their offer, so the planning process is 
underway, and the vacant office of 3rd vice president is now filled.
 
Gerry Naugle presented the treasurer's report. The club is still solvent. Dues and insurance fees 
have been paid to the Rocky Mountain Federation of Mineral Societies. Gerry attended the 
Denver Council November meeting and requested our annual newsletter support grant, which 
was approved. The Council also granted us half of the amount we requested to replace our shed 
last summer. The money has been deposited in our operations account, earmarked for that 
purpose. 
 
The city of Boulder has notified us that room use fees at the Senior Center are going up next year.
Gerry suggested that we could keep our meeting expenses to current levels by canceling the July 
meeting or moving it to another location, such as a park. Our August meeting, the picnic, is already 
elsewhere. The board voted to hold the July meeting somewhere other than the Senior Center.
 
The Elks have been paid for the use of their facilities for our show. The club made a small profit, 
which has gone into operating funds, and the show generated over $400 for the scholarship fund. 
The club also received 20 new membership applications at or following the show. These were 
reviewed and the board voted to accept them. Paul Ralston said new members should be 
introduced at the meeting. Richard Smith reported that the admission information forms 
collected at the admissions desk has generated a mailing list for next year's show. 
 
Gerry pointed out that the Board is required to review the scholarship document annually. He 
recommended keeping the same wording, but update the amounts in the account. The Board 
unanimously accepted his recommendation. 
 
Charlotte Morrison reported that the club's Genie is running hot. Members with mechanical 
expertise are working to diagnose and repair the problem. Two new saw blades have been 
ordered from Diamond Pacific to replace those that broke recently. The board voted to approve 
the expenditure. Discussion ensued. We will no longer order the least expensive sawblades-- 
they break too easily, making it a false economy. If the new ones break, it will be investigated 
and if it was caused by negligence, the person responsible will be asked to share the 
replacement cost. Ray Horton has been supervising saw use ex oficio. People need some 
training to use the saws. Proper adjustment of the saws also requires substantial hand strength, 
which some members lack. We need formal training, qualification, and supervision. The 
discussion was tabled until the January meeting.
 
Ray Horton called the board's attention to the Rockhound Code of Ethics. He said our club's 
observance of it has been lax lately. Certain members have violated the sections regarding 
respect for private property, collecting without permission, violating rules established by the 
property owners, and straying beyond the area in which we were permitted to collect, and in a 
few cases, even getting lost. He suggested that all members should be required to read and sign 
the code on joining the club and when they renew their membership. Gerry Naugle suggested 
putting the code on the back of the club application form with a place for the applicant's 
signature. The board agreed this is a good idea. Ray said there should also be a formal sign-in 
and sign-out for field trips, suggesting that sign-in at the beginning of each field trip should 
include reading and signing a copy of the code. Discussion ensued. Charlotte suggested 
creating a new members' packet. Ray said members should be encouraged to wear their badges 
and have vests. Charlotte has patters and some blue fabric, purchased some years ago for that 
purpose.
 
Ray Horton reminded the board that the club donated 1st and 2nd prizes in geology for the 
Senior and Junior Divisions of last year's Colorado Science and Engineering Fair in Fort Collins. 
We were not mentioned in the fair's literature because we acted too late. If we wish to provide 
prizes again this year, we have to do it by mid-January. The board voted to authorize funds with 
which Ray may purchase prizes to be awarded at the 2004 fair.
 
 
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Updated 1/12/04