Flatirons Facets

Published by The Flatirons Mineral Club

Volume 45, No. 7 July 2003

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 August Facets is July 20.

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President's Corner

Evan D. Elliott (in absentia)

Our esteemed president must be taking some time off to catch up on his fishing, as nothing was received from him this month. However, we know that he and Andrea have been plugging away at getting our November show organized, and they would more than likely have used this space to solicit your participation in our show. This year's show, to be held at the Boulder Elks Lodge, will be a challenge, since it will not benefit from the "walk by" traffic of a shopping mall. There are many ways each of us can contribute, from putting together a specimen case to helping out at the grab bag sale table. So please call Andrea and volunteer!

The July board meeting will be Monday, July 7, at Brad Willkomm's house in Longmont, 7:30 p.m.

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July Meeting (July 10)

Alex Cook

Dinosaur Ridge.

Our speaker will be Joe Tempel, executive director of Friends of Dinosaur Ridge. Joe is in charge of the Dinosaur Ridge Visitors Center, which organizes groups of people to visit the Ridge, which as we all know, is one of the richest depositories of dinosaur fossils in the Western United States. Joe has been with the Colorado Department of Transportation, dealing with the Environment and Planning since 1967 and was one of the founders of Friends of Dinosaur Ridge when it was organized in 1989.

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From The Field

Paul Boni

Oh, my goodness! Where shall I begin? The last few field trips have been so much fun. I want to thank all of the hole digging and rock breaking faithful for making for making these outings so entertaining and successful.

Calumet Iron Mine and Ruby Mountain; Thank you Alex (Cook) for guiding us to the perlite and apache tears on Ruby Mountain. We were able to fill a 5-gallon bucket with grab bag samples and all we wanted for ourselves. The back side of Ruby Mountain turned out to have garnets and topaz in the same concentrations and quality as the front side. We also recovered a ten-year-old boy who had wandered away from his parents and then turned the entire family of five onto rock hounding. More converts! Then it was on to the Mt. Princeton hot springs for a soak and then to camp.

Our day at the Calumet Iron Mine turned out to be the most successful yet. It didn't take long for new club member Bret Medici to locate a zone showing plentiful calcite pockets lined by epidote and quartz. It did take us the rest of the morning to break up a very resistant boulder. But we all pitched in and extracted specimens enough to go around. It would not surprise me to see one of these take the prize at the towel show.

Crystal Peak; A great (huge!) thank you goes out to Jeff and Donna for inviting us to dig on their claim. Although nobody unearthed that elusive plate of amazonite and smoky quartz, everybody found something. Amazonite, microcline, smoky quartz, and fluorite all make into our buckets and bags. We were also able collect a few hundred chunks and partial crystals of amazonite and microcline for the grab bags.

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Field trips

Paul Boni

July 4-7: Spencer opal mine, Spencer, Idaho. Trip leader, Paul Boni. A few of us will be traveling to Spencer Idaho to dig in the tailings at the famous Spencer Opal Mine. Day 1) Travel to Lava Hot Springs, ID (8 hrs driving) to relax and enjoy the fire works and the fine hot springs. Day 2) Travel to Spencer (3hrs driving) and set up camp. That afternoon we will search for gem plagioclase (sun stone) at a nearby cinder cone. Day 3) Search the mine dump for precious opal! This is a fee dig area. The cost is $30.00 per person and includes the first five pounds of opal. There is an additional fee of $5.00 per pound after the initial 5. Day 4)... I will be staying on at Spencer. Participants are free to wander where they will from this point. Yellowstone is a half-day to the east. Montana is a hop, skip, and jump to the north. Crystal Park, and the Rock Creek sapphire claims are available. Western Idaho is famous for its jaspers and agates as well.

August 10(?): Mt. Antero (tentative) Trip Leader; Paul Boni. Final arrangements have not been made as of this writing. More information will follow. Craig Cardwell enjoyed our company last year and would like to have us back. In addition to our having a good time digging last year, we (the accumulated rock hounds from a few different clubs) managed to uncover a large pegmatite. Craig was thrilled! This trip will be in conjunction with the Contin' Tail rock show at the Buena Vista rodeo grounds. The show runs Friday (9th) through Sunday (11th). It's all outdoors with rows and rows of dealers and rock hounds. If you haven't been to the Contin' Tail yet, well... you don't know what you're missing.

The field trip schedule is light for July. I'm out of town and no one else stepped up to lead a trip. Well, perhaps someone will get an itch and announce one at the July Meeting

Paul Boni is seeking volunteers to lead trips. Trips may be announced at the club meetings, or you can contact Paul to find out about any upcoming trips, or to volunteer to lead one.

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FMC Annual Club Picnic, Saturday August 16

The annual club picnic will be on Sat. August 16th from 4:00pm to about 8:30pm, to be located at the main pavilion at the North Boulder Park. The North Boulder Park pavilion is located just west and just north of the Boulder Community Hospital entrance at west Balsam Ave. and 9th St.

The Club will provide the meat (and veggie burgers), potato salad and macaroni salad. There is adequate table space there for working on and completing the grab bags prior to dining. Outdoor charcoal grills are located there.

Club members whose last name starts below M are asked to bring salads or baked beans. Club members whose last names start after M are asked to bring breads or desserts, including watermelon. The club will provide the chilled beverages and bottled water.

Please RSVP to Gerry Naugle by Aug 14th.

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Get Acquainted With The Boulder Elks Lodge

The Boulder Elks Lodge will be the site of our Fall Show, and we even considered these fine facilities for our August picnic. The Elks would like everyone to know that each Friday evening during this summer, the Boulder Elks Lodge is having free swimming in their big pool, and the public is invited to come on out. It is possible to purchase BBQ food for dinner there also.

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Flatirons Mineral Club Show -- Nov. 14,15,16, 2003

Jeanne Hurst

Show Flyers are now in print--get copies from Andrea Elliott or at any club or show meeting. Volunteers contact Andrea Elliott Dealers contact Gerry Naugle or John Hurst.

Help! Help! We still need help in the following committees:

1. Denver Showcases-we need strong bodies and pickups to handle the pick-up, set-up and return of the Denver Show cases.

2. Youth Chair-to help coordinate the Grab Bag Fishing Pond, the Kid's Wheel, the Pre-School Dig site, the Scavenger Hunt, etc.

3. Working Demos Chair to coordinate equipment & volunteers to show the public how fun the lapidary arts can be.

4. Ultra-Violet Room Chair to arrange the set up of the dark room, the U-V lamps and displays.

5. Introductory Classes Chair to line up mentors for mini-classes and/or slide programs, for example: 1st Class--Bola Ties Made Simple.

6. Signs & Sound System Chair to arrange and set up a sound system and organize volunteers to make and place signs for the show.

7. Field Trip Chair to lead a field trip on the Monday after the show, November 17, weather permitting.

8. Colorado Mineral Map Chair to organize a team to set up and break down our Colorado Mineral Map. It's a great chance to learn!

DONATIONS OF ROCKS ARE NEEDED

Bring rocks for the Children's Wheel to Martha Ralston or the next Show Committee meeting. We are virtually out and drastically need to restock our supply for the "Wheel". Bring rocks with label information to Charlotte Morrison for stuffing our grab bags. We always need more, so clean your garage, your basement and your yards!

We need young strong bodies and pickups to haul and set up Denver Cases. Paul Ralston is working on lining up exhibitors; he will be able to offer advice and guidance to our "Strength Team". Gerry Naugle reports we are already up to five dealers. If you have a favorite dealer or two, please put them in touch with Gerry Naugle or with John Hurst .

Thank you to Bill Vanderminden, William Smith and "mystery lady" for their donation of fabric for the sewing of grab bags.

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Upcoming Events, Nearby & Elsewhere

July 4-7, Flatirons Mineral Club field trip to the Spencer Opal Mine in Spencer, Idaho-a 4-day weekend expedition! See p. 1 for details.

July 11-13, RMFMS Show and Convention, Casper, WY., "Treasures of the Rockies", hosted by the Natrona County Rockhounds Club. Show Location: Parkway Plaza Hotel and Convention Center (at I-25 and Center St.), Casper, WY. Contacts: Ed Mcknire 307-265-6202.

July 11-13, 50th Annual Four Corners Gem & Mineral Show, LaPlata Fairgrounds Exhibit Hall, Durango Durango, CO. Contact Marie Wester

July 29 (Tues.) 11:30 a.m.-1p.m. and July 30 (Wed.) 7 p.m., Denver Museum Of Nature and Science Lecture: Meteorite Hunting in Antarctica, presented by Andy Caldwell, Research Associate. Denver Museum of Nature and Science, Ricketson Auditorium. Mr. Caldwell shares the results of the 2002-2003 Antarctic meteorite field season, and the science and recovery process of meteorites. Admission: Tues. - $6 member, $9 nonmember ; Wed. - $10 member, $13 nonmember.

Aug. 10, Flatirons Mineral Club field trip to Mt. Antero (Paul Boni, leader), in conjunction with the Contin' Tail Mineral Show in Buena Vista, August 9-10.

Aug 16, Flatirons Mineral Club Annual Picnic, North Boulder Park pavilion, 3:30 PM to dark.

Sep. 10-14, Denver Gem and Mineral Show, (Denver Merchandise Mart, Sep. 12-14), and the companion "Colorado Fossil Expo" (in part of the same building, single admission for both shows) and the separate "Colorado Mineral and Fossil Show", Sep. 10-14 (no admission charge) at the Holiday Inn Denver North, 4849 Bannock St. (I-25 west side frontage road, just north of I-70)

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Mineral Terms Quiz

From Quarry Quips, Nov. 2002, newsletter of the Wichita Gem & Mineral Society

Test Your Knowledge of Mineral Terms: Match the Term (on the left) with the Description (on the right)

1. Adamantine A resistance to abrasion or scratching

2. Alluvial B formed of slender bundles of fibers

3. Amorphous C composed of closely packed grains

4. Amygdaloid D almond-shaped cavity such as agate forms in

5. Asterism E splitting in a definite plane

6. Botryoidal F mineral shell filled with crystallized minerals

7. Brittle G brilliant luster like that of a diamond

8. Chatoyant H firmly united

9. Cleavable I having definite crystal structure

10. Compact J fracture surface covered with sharp points like that of cast iron

11. Conchoidal K composed of crystals so tiny their form is invisible

12. Conglomerate L star-like effect of rays of light on gem surface

13. Crypto-crystalline M deposits made by running water

14. Crystalline N shaped like a bunch of grapes

15. Cubic O cube-like, applied to crystals

16. Dendritic P crystalline igneous rock formed principally of quartz and feldspar

17. Fibrous Q formed of thin layers or sheets

18. Foliated R without crystal structure

19. Fracture S reflecting light in pattern like that of a cat's eye

20. Geode T appearance of broken face of mineral

21. Gneiss U metamorphic laminated rock

22. Granite V rock made up of worn fragments cemented together

23. Granular W having tree-like patterns

24. Hackly X fracture surface curved like that of a seashell

25. Hardness Y easily fractured

Answers below.

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The Cullinan Diamond

R.C. Bissonnette

On January 25, 1905, Frederick Wells, Superintendent of the South African Premier Diamond Mine, was making his final rounds of the day when one of the workers ran up to him. The worker was so excited that he could hardly speak. He led Wells to a spot where he pointed to something embedded in the wall of the mine which sparkled in the rays of the setting sun. Wells thought it was just another joke, which the workers sometimes played on each other, but he entered the hole anyway and dug from the wall an object that turned out to be the largest gem quality diamond ever found.

The 3,106-carat (1.37 lbs) near flawless, near colorless giant was more than three times larger then the previously largest rough diamond. The crystal was named the Cullinan in honor of Sir Thomas Cullinan, the found of the Premier Mine, who happened to be visiting the mine on the day it was found. In 1908 the Cape Colony government purchased the crystal and gave it to King Edward VII on his sixtieth birthday.

The task of cutting the crystal was given to Amsterdam's House of Asscher who studied the rough for several months and experimented with glass and wax models before starting the cleaving operation. The initial cleaving took place at 2:45 P.M. on February 10, 1908 when Joseph Asscher placed a specially designed steel knife in a groove that he had previously sawed in the rough. He struck the knife with a steel rod and nothing happened. He struck the knife a second time and the crystal cleaved as planned. The crystal was later cleaved into 3 major pieces, then into 9 large and 96 smaller pieces, which were later faceted into 105 finished gems.

The nine major gems were designated Cullinan I through Cullinan IX. The largest, Cullinan I, also known as The Star of Africa, is a 530.20 carat pear-shaped gem which is the largest fashioned diamond in the world. It is mounted in the Scepter of the British Monarch. Cullinan II is a 317.40-carat cushioned-shaped gem that is also part of the British crown Jewels. It is mounted in the Imperial State Crown. Both are kept in the Tower of London. The remaining seven major Cullinan gems were kept by the Asschers as payment for their labor. They are the Cullinan III, a 94.4 carat pear; Cullinan IV, a 63.6 carat square-cushion; Cullinan V, a 18.5 carat heart; Cullinan VI, an 11.5 carat marquise; Cullinan VII, an 8.8 carat marquise; other tests to make the determination. Denver Post, May 12, 2003.

See the Cullinan Diamond Replicas display from the Mineral and Lapidary Museum of Henderson County, North Carolina at the 2003 Denver Gem & Mineral Show!

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Hints And Tips

Tiger-Eye: For that glass finish on tiger-eye, polish once, dry the stone, then put a drop of vinegar on the stone. Leave it on for a couple of minutes, and then give it a second polish. The result should be that deep glass finish that you've been wishing for. (Source: Gem & Mineral Federation of Canada, August 1989, via "Rock Chips", August 2001)

To finish soapstone as the Chinese did, heat the finished carving in the oven for an hour at 200 degrees. Remove from the oven and apply a coat of paste wax and polish. A jade effect results from this method. (Source: Golden Spike News, July 2004, via "Rock Chips", August 2001)

Add a couple of pouches of Knox Gelatin during each grit change when tumbling. This keeps grit in suspension and works better in the cutting process. In the final polish the gelatin acts as a cushion and prevents scratching on delicate stones. (Source: Rock Chipper, via Gear Time, August 2001)

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Agates

Author unknown (source: Pebbles, Apr. 2000, via Quarry Quips, June 2003)

A process which took nature hundreds, thousands or perhaps millions of years to complete cannot be covered easily in a few words, but lets take a simplified version of their creation: First came the raw material, silica (silicon dioxide SiO2). This compound is a combination of silicon and oxygen and is a major rock builder in the earth's crust, being second only to the compound water in abundance. With silica so common, gems should be everywhere, but their formation depended upon special conditions, and this is where our story begins.

About 400 million years ago the Pacific Northwest began to rise from the sea. In a succession of volcanic upheavals, a landmass rich in silica was created. Occasionally these lavas cooled so rapidly they formed a volcanic glass, obsidian. Generally, however, volcanic masses cooled slowly, tended to crystallize and were porous, eventually breaking down to release minute particles of silica. This free silica, in turn, was dissolved by acids in percolating ground waters, then transported and finally deposited as concentrated liquids in subsurface cavities. Experts differ on how the liquids eventually became solids; however, the following basic silica forms were the result.

Crystalline - Silica deposited in obvious crystal forms and known as quartz or rock crystal.

Opaline - A silica form similar to chalcedony but totally non-crystalline, more porous and containing small-added amounts of free water (3 to 14 percent) held within its structure rather than its chemistry. Gem opals are of this form.

Cryptocrystalline - Silica deposits of microscopically fine-grained, almost noncrystalline masses known as chalcedony. Chalcedony characterizes agate and jasper.

Each of these silica forms occurred within cavities of previously formed rock and is termed secondary deposits. How each formed, however, depended largely on where it formed.

Individual gemstones, when found in gravel bars or loose soil, are usually a long way from their birthplace, having rolled and tumbled with the eroding forces. Generally the surface landmass of their origin has long since crumbled and vanished. However, some gems are still embedded where they developed and show that each basic type resulted from its own characteristic surroundings.

Agate: The result of Chalcedony, which filled empty gas pockets or cracks in otherwise solid rock, forming as nodules or seams. Since only limited amounts of foreign materials were included, the stone is fairly pure and ranges from clear to translucent when held to the light. Not all agate formed this way with the two exceptions being thunder eggs and fossils.

Recognizing and Testing Agate: The mineral world has many look-alikes, but not all have gemstone quality. To avoid filling your pockets with excess rock, three simple tests can be made:

Luster: Look for even-textured, non-granular material ranging from clear (glasslike) through translucent (semi-clear) to opaque (blocking out light). Rough specimens may have a glassy, waxy, pearly or even dull appearance and can be better judged when wet. Agate: Waxy, clear to near opaque. Jasper: Waxy to dull and opaque. Opal: Pearl-like, clear to opaque.

Fracture: Broken edges are usually conchoidal (cupped, shell-like fractures as on a chunk of glass). Water-worn pebbles often show curved, crescent-like surface markings. An exception to this is opal, which tends to be brittle and more angular in fracture.

Hardness: Part of the reason these are termed gemstones is in their ability to polish well and withstand abrasion. They rank between 7 to 7.5 on the Mohs hardness scale.

Probably no gemstone is known in a greater variety of colors and patterns than agates. And like fingerprints, no two of these are ever exactly the same. However, recurring agate character types have been given appropriate names such as: White or Milk Agate, Turtle-Back, Coated Agate, Snakeskin Agate, Blue Agate, Amethystine Agate, Carnelian, Sard, Polka Dot, Sunset Enhydro or Water Agate, Fortification Agate, Iris or Rainbow Agate, Banded Agate, Sardonyx, Grape, Eye Agate or Orbicular, Tube or Pipe Agate, Angel Wing, Dendriditic, Moss, Plume, Flower, Sagenite Agate and our own Ellensburg Blue Agate.

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Mineral Terms Quiz Answers

1-G, 2-M, 3-R, 4-D, 5-L, 6-N, 7-Y, 8-S, 9-E, 10-H, 11-X, 12-V, 13-K, 14-I, 15-O, 16-W, 17-B,

18-Q, 19-T, 20-F, 21-U, 22-P, 23-C, 24-J, 25-A

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Minutes of the Board Meeting, June 9, 2003

Emily Epstein, Secretary

Present: Paul Boni, Alex Cook, Emily Epstein, Ray Horton, Charlotte Morrison, Gerry Naugle, Paul Ralston, Melinda Thompson, Brad Wilkomm, Lew Yoder

Paul Ralston urged board members to urge club members to contribute specimens for grab bags and the children's wheel.

Gerry and Andrea have finalized the contract with the Elks' Lodge for our fall show. There will be gold panning, and we will have a secured closet for storage as well as a room that can be set up for a fluorescent display. Gerry has also asked whether the Elks would be willing to let us use a little space on their property for our shed. Our deadline to move the shed is July 30. There is also a possibility that we could hold meetings there if the rumored raise in cost at the Senior Center occurs next fall.

Melinda Thompson reminded the board that we want at least 12 dealers at our show, and we still need volunteers for several key jobs. We also need to put together a slate of candidates for the election in October. The board agreed to ask Dennis Gertenbach to chair the nominations committee. Other possible members for the committee were discussed.

Ray reported on some possible locations he has scouted for the shed. As yet, we have no firm possibility in or near Boulder. Gerry pointed out that the shed is in bad shape. The Denver Council will decide on our grant proposal to replace it with a new Tuff Shed later this month. Whether we get the grant or not, the structure needs to be replaced. Paul Ralston said that he could use parts of the shed, if nobody else wants it. After some discussion, it was decided that we would call for bids, and when we move the club's property out of it, the high bidder can have it.

Ray urged the board to write to the Denver Mint suggesting a gold miner for the Colorado quarter. At the meeting on Thursday, he will ask members to write individually.

Melinda pointed out that many clubs do not meet in the summer, and asked whether we should consider taking a break as well. Since the programs are already set up for this summer, the discussion would only apply to summer 2004, so the matter was tabled until after the new board is elected in October.

 
 
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