Strata Gem

January 2005

 

The Presidents Message

 

As this will be my last message to you as your President, I want to thank all my officers for a job well done. Many thanks to all.

 

Our Christmas Party was a great success, we had 39 people there. The food was great and my husband felt like he could sing a couple of songs. He hadn't been able to sing for 3 years and has been under a doctors care.

 

Our new President has been there before and I know he will do a great job.

 

Some members paid their dues at our party, there will probably be more at our meeting.

 

   Love to you all

   Your President

   Ruth S Smith

 

Answering Machine Message for the Mental Health Institute

 

·        Hello, and welcome to the Mental Health Hotline.

·        If you are obsessive or compulsive, press 1 repeatedly.

·        If you are co-dependent, please ask someone to press 2 for you. If you have multiple personalities, please press 3,4,5 and 6 If you are paranoid, we already know who you are, but stay on the line while we trace your call.

·        If you are delusional, press 7 and your call will be transferred to the mother ship.

·        If you are schizophrenic, listen carefully and a small voice will tell you which number to press.

·        If you have short term memory loss, press 9, if you have short term memory loss, press 9, if you have short term memory loss, press 9.

·        If you have low self esteem, please hang up. All our operators are too busy to talk to you.

 

Via Gravel Gazette 5/04

 

Time Rocks
collected by Chris Fite, Aug 2002

 

Some of the most interesting rocks to look at have layers or bands. They form a pattern that apparently could only have been made by some kind of event repeating itself, like repeated flood waters that lay down layer upon layer of Sandstone to form "Picture Rock" Sandstone. These rocks record a sequence of events that occurred over a span of time, analogous to a movie film recording a series of images from instant to instant. I call these rocks "TIME ROCKS", because they obviously show a sequence of reoccurring events recorded over a period of time. Other examples are banded Agate (rhythmic crystallization from molten Quartz) or banded limy Travertine (hot water depositing dissolved Calcite).

 

There are other TIME ROCKS that obviously record only a single instant in time. They are analogous to a single photograph instead of a movie film. An example would be a fossil (the death and burial of a creature), or the thin layer of white ash bisecting a piece of obsidian that I have, showing an instant in time when a volcanic ashfall occurred. The large piece of chert that I found with a boundary separating white from gray regions with fossils only in one color area shows a singular event, the underwater avalanche of ocean bottom ooze that covered and killed all the sea floor creatures at that instant several hundred million years ago in Oklahoma (or perhaps it was a sudden ashfall from a volcano?).

 

There are still other TIME ROCKS that record several unrelated events, often separated by long periods of time, perhaps millions of years. These rocks can be decoded with the aid of the information in good rock and mineral books. These time rocks are like a stack of several photos taken of several different items. An example is a rock slab that I bought two years ago. The bulk of the rock was blue with smaller blobs of dark gray rock and with thin streaks of white rock. Testing those rocks showed that the blue rock was Sodalite (has salt in its chemical makeup and is associated with volcanoes), the white streaks were Dolomite (associated with Limestone, which is associated with Magnetite), and the dark gray blobs were Magnetite. So, long ago, an ocean dried up leaving a layer of salt and a layer of limestone. Then Magnetite was deposited in the Limestone. Then the Limestone changed to Dolomite stone. Then a volcano erupted and forced molten lava into the salt, reacting with it to form Sodalite, and at the sae time, forcing the molten Sodalite into the layer of Dolomite stone that contained the Magnetite. So, several isolated events, occurring over a period of hundreds of millions of years, resulted in Sodalite mixed with Dolomite and Magnetite.

 

Finally, some TIME ROCKS, to the lay person, show no signs of time whatsoever. An example is the slow nuclear decay of radioactive substances within some rocks which, to an expert equipped with expensive tools, can tell him how old the rock is.

 

Via T-Town Rockhound 7/04

 

Citrine, The "Brown Amethyst"

 

Citrine is a yellow to orangish-brown-colored quartz of gem quality. Its name is derived from the French word citron, which means lemon, and naturally occurring citrine tends to be a pale yellow. However, most of what is on the market is actually lower-grade Brazilian amethyst that has been heated to about 500 degrees centigrade, or 932 degrees Fahrenheit; this citrine tends to have more of an orange or red caste. Both amethyst and citrine get their coloring from the presence of iron in the quartz; the process of heating the amethyst reduces the oxidation state of the iron impurities and fades the purple coloring.

 

Since citrine is so closely associated with amethyst, it is sometimes possible to find both colors in the same stone. When this happens, you have a gem that is called ametrine. It is often faceted so that the resulting gemstone is a 50/50 mix of the citrine and amethyst, making for a very showy piece indeed. This particular gemstone has only been on the market for about 30 years.

 

Citrine stands as a gemstone in its own right, however, as one of the most valuable and popular of the quartz gems. It is listed both as the November birthstone and the anniversary gemstone for the 17^th year of marriage. Because of its availability and affordability, it is also a popular alternative to the more expensive topazes, yellow sapphires, and yellow diamonds.

 

Despite its beauty, citrine does have a few drawbacks. Because it has already undergone some natural alteration, its coloring is somewhat unstable, and prolonged exposure to sunlight can fade it, giving it a pale, washed-out appearance. Despite its hardness, it is somewhat brittle, and can be scratched fairly easily. Also, in determining the true value of a particular stone, it is not possible at this time to determine whether or not the citrine was synthetically heated. You don't have to worry about being duped with truly synthetic citrine, though; it's too expensive to produce.

 

Finally, a few technical notes: citrine's chemical composition is SiO₂ (silicon dioxide) with minor Fe3+ impurities causing the coloration. Citrine has a hardness of 7, a conchoidal fracture, a white streak, no cleavage, and a vitreous luster. It is transparent to translucent. The crystal structure is macrocrystalline, which means that you can see the individual crystals with the naked eye, as opposed to cryptocrystalline, which means that you cannot discern the individual crystals unaided. The shape of the crystals is hexagonal. Citrine most commonly occurs as protruding clusters of crystals on a geode base, with an igneous origin.

 

BIBLIOGRAPHY:

Amethyst Galleries, Inc., "Citrine, the Yellow and Orange Variety of Quartz,^" 1996, 5/10/2004, http://mineral.galleries.com

 

Eid, Alain, 1000 Photos of Mineral and Fossils, Barron's Educational Series, Hauppauge, NY, 2000.

 

Friedman, Hershel, "Citrine: Yellow to Brown Variety of Quartz," 2003, 5/10/2004, http://www.minerals.net

 

Gem and Mineral Miners Inc., "Citrine: Mineral Information Page,^" January 14, 2001, 5/10/2004, http://www.mineralminers.com

 

Jewelry Mall, "Citrine," 1999, 5/10/2004, http://www.jewelrymall.com

 

Post, Jeffrey E., The National Gem Collection, Harry N. Abrams, Inc., New York, 1997.

 

Via T-Town Rockhound 7/04

 

Fiber Optic Gems: What are They?

By Bill Grimes

 

Fiber optics were developed as a result of someone studying a piece of the mineral ulexite. Also know as TV stone. It is a hard, brittle, fibrous stone which - when writing is placed underneath - will allow the image to appear on the surface of the stone. This led to the theory that if this type of fibrous material could be manufactured, it could be used in many different ways where image transmission is needed. Fiber optic cables were at first very slender and flexible, used in surgeries and in household decorations.

 

The manufacturing technology improved and soon manufacturers were spinning out miles of cable for a new application, data transmission lines. These lines can be up to two inches across. The cable consists of thousands of pairs of optic fibers. Each pair carries data for phone, computer, fax, etc. Since the sides of the cable are reflective, there is no need for insulation or shielding around each fiber, as in old phone lines. This translates to more pairs in a smaller space. For us in the hobby, this created one of the newest gem treasures - fiber optic cabs.

 

In order to make a fiber optic cabochon, the cable scraps are first cut into small lengths. The cable is then either cut into spheres, or it is sectioned parallel to the length of the fiber, once the slices are made, it is cut much like any other gem. Care must be taken, however, to protect the ends of the cable from splintering, or catching dirt, abrasives, etc.

 

There is an interesting thing about fiber optic gems. If you look at them from a 90° angle from the eye of the gem, the gem will be transparent to light, maintaining its properties for light transmission.

 

Originally from Rockhouse Roundup, 3/99

via the BEMS Tumbler, 7/04.

Via Golden Spike News 8/04

 

Sunstone Of The Vikings?

 

The mineral Cordierite is thought to be the source of the famous sunstone of the Vikings, who, in the ninth century, were expert navigators. Without benefit of compass, Viking sailors managed to ply their watery routes of conquest and commerce, navigating by the stars at night and the sun during the day. No matter what the weather, according to ancient Scandinavian sagas, the sun could be located with the aid of the magical "Sun Stone." Summarizing sun stone lore in a recent article in the archaeology magazine "Skalk", Danish Archaeologist Thorkild Ramskau, lamented that none of the sagas clearly describe the sun stone. "But there seems to be a possibility," he wrote, "that it was an instrument which, in cloudy weather, would show where the sun was." Now, with a clue supplied by a young archaeology enthusiast, Ramskau has discovered the secret of the sun seeking stone of the ancients.

 

To the ten-year-old son of Jorgen Jensen, Chief navigator of the Scandinavian Airline System, the instrument described in "Skalk" sounded like the twilight compass used by his father at higher altitudes, where the magnetic compass is unreliable. The twilight compass is equipped with a Polaroid filter that enables a navigator to locate the sun, even when it is behind the clouds or below the horizon, by the light polarized by the atmosphere. Intrigued by his son's observation, Jensen passed it on to Ramskau, who immediately recognized its scientific implication. Enlisting the aid of Denmark's Royal Court Jeweler, the archaeologist collected minerals found in Scandinavia whose molecules are aligned parallel to each other just as the crystals are in a Polaroid filter. Ramskau found one of these minerals, a transparent crystal called cordierite, turned from gray to violet-blue whenever its natural molecular alignment was held at right angles to the plane of polarized light from the sun. Thus, he reasoned, a Viking could have located the sun by rotating a chunk of cordierite until it turned blue.

 

Putting cordierite to the test, Ramskau accompanied navigator Jensen on a S.A.S. flight to Greenland, keeping track of the sun with his stone while Jensen used the twilight compass. His observations were accurate within 2 1/2 degrees of the sun's true position, and he was able to track the sun until it dipped 7 degrees below the horizon.

 

"I now feel convinced," Ramskau concludes, "that the old Vikings, with the aid of their sun stones, could navigate with enormous accuracy."

 

Ed. Note: Cordierite is known in the gem trade as lolite.

From Stone Age News. Nov., 1993, via Northwest Newsletter. Jan 1994

Via Gneiss Times 4/02

 

Enamel Beads

By Don Bykerk, member of the Shawnee G&M

 

Making enamel glass beads is relatively simple and easy and the cost is modest. The end products (beads) are both beautiful and functional. While it is possible to make beads which appear similar, no two beads are ever the same, and therein lies the fun in doing this kind of lapidary work. Experiment with mixing colors (there are hundreds) and techniques to create different shapes.

 

Enamel Glass is somewhat hard to find as few craft shops stock it. I have found that the best place to secure it is by ordering from Thompson Enamel, Inc. If you call them, they will send you a catalog. The catalog also contains useful information on distributors over the country, publication, findings for enameling, etc.

Thompson Enamel, Inc.

650 Colfax Ave.

Bellevue, KY 41073

Phone: 1-859-291-3800 (toll Free)

Web site: http://www.thompsonenamel.com

 

Equipment needed

The crucial piece of equipment is a work board. This is necessary to protect any other surface you do not want burned, marred or marked from hot glass and I can promise you it will happen sooner or later. If you are fortunate enough to have or can find an old asbestos siding shingle or other piece of hard asbestos, approximately 18-20 inches square, you can glue it down on a piece of plywood and you are all set to go after installing a short piece of steel shelving rail which is used to pull a bead off the rod when you are done. You can also use some of the newer inflammable materials, but make sure they have a very hard surface. Most of these I have found have a fuzzy-like texture and this mars your hot bead when you pull it off the turning rod. You can avoid this by wrapping the piece in foil. *Disposable propane tank (Walmart)

·     Propane Torch Tip (Walmart)

·     Stainless Steel Welding Rod 1/16, 3/32, 1/8 sizes, cut into 12 to 15 inch lengths (Welding Supplier)

·     4x6 index cards or pieces of foil cut to this approximate size to put powered or broken glass on.

·     1/16, 3/32, or 1/8 copper tubing cut into 1/4, 3/8, Y2, 5/8; & 3/4 lengths.

·      Bead base. Most automotive carry this or can get it but get the smallest OD that you can.

·     A small cake decorator's spatula

 

You may need to shape your rods by grinding a long tapered end on one end if you are unable to locate small size welding rod.

 

Getting started

Once you have secured your glass and are ready to try your hand at bead making proceed as follows, but don't be afraid to experiment and try something different. I have seen almost every shape imaginable in every color of the rainbow, and mixtures which I cannot hope to describe. Some are also luminescent and are strikingly beautiful.

 

Place a selected piece of copper tubing on your rod and make sure that part of the rod is exposed on the top end. This is important because if you fail to do so the glass will fill the end and you will not be able thread the bead on wire or cord after it cools. Next heat the copper tubing in the propane torch until it glows cherry red. Quickly roll the heated piece in a row of base material, either clear or opaque. When it is fully coated with base material, re-heat it until it again glows bright red. Again roll it in the base material until well coated. Re-heat and repeat three to five times depending upon the size of your bead. Then reheat and roll it in your color material until coated. Repeat and reheat until desired shape and size is reached. At this point you have, for all practical purposes, a completed bead. If you want, however, you can decorate your bead by heating it and then picking up some broken pieces of glass of a different color and reheating until it melt into the body of the bead. At this point and while still very hot, hook the backside of your bead in the crotch of your steel shelve bracket and pull it off the rod. Be careful that you do not let it slip up and off the copper tubing or you deform the glass and have to reheat and reshape it and you run the risk of losing your color design, although 1 have had some surprising results when this occurred. The biggest problem with this is trying to make a similar match. Its always best to do it where you have controlled the results.

 

The results

Once you have completed two or more beads you can fashion them into French earrings, necklaces, pendants, or incorporate then with other and different beads, such as gold or silver beads to create a very lovely necklace. Let your imagination run wild and you will be pleasantly surprised with the results.

 

So... What is Dichroic Glass?

 

Dichroic (di'kro-ik) glass is any glass that is coated with metallic oxides such as silicon, titanium and magnesium in a vacuum furnace using technology called thin-film physics. Dichroic means "Two colors" and the glass is called this because it reflects one color but transmits another (the color you see when you hold the glass up to the light and look through it). Dichroic glass is commonly used 1 the laser industry and in scientific measuring equipment. You may be most familiar with dichroic filters for 35mm cameras or in Pia headlights for cars. It is truly a medium for the 21^st Century.

 

(The following is a report of a class the Fresno Gem & Mineral class had on making dichroic glass. The way it was written made it inconvenient to shorten or summarize. Perhaps we can be inspired to make some dichroic glass cabs'?)

 

In March we had our first Dichroic Glass Class here in our FGMS Classroom. Judi Gooch, the instructor and her husband, Gary, came down the hill and taught this really fun class. We all met by 10:00 AM, picked out our glass, and settled down to work. Each of us had picked up at least 2--4"x 6" bottom pieces and 6 to 7 much smaller pieces of the dichroic glass.

 

Each piece was individually priced. My total was $18.75 + $5.00 for tiring, so my total for he day was $23.75 and I still have a lot of glass left over for another class. The size limit for our individual pieces is 1" x 2" and we could make- a maximum of 8 pieces. Judy G. supplied all the table coverings and tools. Gary G. was at the ready by the three kilns they had brought with them.

 

All of us started cutting glass and the fun began. I was very worried that I would not be able to hold the glasscutter, but the glasscutters Judy brought were very wonderful and the glass broke evenly and easily. After getting our shape all worked out on the bottom piece then we put on the dichroic glass. Everyone worked very differently. Some fitted them on like a mosaic, others laid them out in a creative style, some were simple and some were complex. We had all picked out different colors, so there were different looks and colors everywhere.

 

When we finished Gary would come around and carefully pick up our pieces and take them to the kiln. He carefully made a chart of whose pieces were where because after they are fired it is hard to recognize your own work. In 15 minutes they were finished and Oh! They were beautiful!

 

Via Rock Chips 7/04

 

Keeping Public Lands Public

From Bob Cranston

 

This was sent to me by an officer in the BLM. I think his advice is good and if anyone wants to protect their rock collecting privileges, this would be one good way to start. The other and best way is to get off our duff’s and do something. First download and print out and digest the 7.3 megabytes of material listed below. If you can’t digest it and make a decision, get some help. There are at least a couple of lawyers in our group and although they are up to their ears in work, they will talk to you.

 

If you print this out, you will have the e-mails of at least a couple of them. They are your peers, so don’t hesitate to talk to them.

 

I am purposefully omitting the name of the BLM officer who sent this to me, so he doesn’t have to answer questions of WHY? from superiors.

 

Keeping Public Lands Public

 

Dear fellow rock hunter recreationists:

Today I stumbled upon a valuable document that can help all of us fight for the use of public lands to continue our hobby.

 

We can take a page out of the other side’s book to assist our efforts to participate in the resource management decisions of the BLM and the US Forest Service that may unjustly restrict our rights and abilities to collect rocks, fossils and minerals.

 

Actually, this is 7.3 megabytes of pages from the Wilderness Society “book” titled “A Conservationist’s Guide to BLM Planning and Decision-Making Using FLPMA and NEPA to Protect Public Lands.”

www.wilderness.org/Library/Documents/upload/BLM-Citizen-s-Guide-full-report.pdf

 

Just as the wilderness advocates can use knowledge about federal agency decision-making and processes to lock us out of public lands, rockhounds can take the same knowledge to present opposing information and perspectives. Each of us can become informed about what’s being planned in areas of collecting that are our favorites. Personal visits to ranger stations, field trips with the geologists or recreation planners are valuable to make ourselves know and our interests heard. Participating in the planning processes also gives us “standing” to protest or appeal decisions that are made against our hobby in spite of our previous inputs.

 

Rockhounds don’t have the multi-million dollar budgets of the eco-scare organizations, but we can use our existing club and federation contacts to lobby agency managers and legislators. If we could team with like-minded groups that would amplify our voices.

 

A personal pitch of mine is for us to keep other political agendas separate from our interest in either promoting responsible collecting opportunities or opposing unreasonable restrictions. Some of the other groups that support access to public lands have tended to attach unrelated philosophies and themes, such as right to bear arms, and property rights, for examples, to their messages. These themes may be important in themselves but they distract from our main interest and shift discussion from facts to opinions and emotional responses.

 

Last item: A plug for the Barstow BLM office website pages on rockhunting in the Barstow, CA area.

<www.ca.blm.gov/barstow/rock.html>

 

This is an excellent summary of collecting rules and some descriptions of local collecting sites. I haven’t confirmed it, but I suspect Harold Johnson, Recreation Chief of the Barstow BLM office is to thank for the good work.

 

Via AFMS Dec/Jan 2005