The Ventura Gem & Mineral Society, Inc. (VGMS)

Gem, Mineral and Fossil Information 1998 Archive.

Table of Contents.

1. JANUARY - HISTORICAL MINING & MINERAL EXHIBIT By Jack V. Woods;
2. JANUARY - April 1956-BRITTINGHAM (Ventura Jr College Geology professor) STUDENTS MAKE RARE DISCOVERY;
3. JANUARY - INTERESTING MINING FACTS;
4. FEBRUARY - FOSSIL IMPRINTS;
5. MARCH - A MOUNT FOR REALLY SMALL SPECIMENS By B. L. Benson;
6. MARCH - MORE ON THE SMALL MICROMOUNT;
7. APRIL -"THE JADES: COLORS AND CONTROVERSIES" By Lyle G. Gable;
8. JUNE - GEODES;
9. JULY - THE BIGGEST, THE BEST, AND THE MOST GARGANTUAN;
10. JULY - A LITTLE ABOUT PETRIFICATION.

January.

HISTORICAL MINING & MINERAL EXHIBIT By Jack V. Woods, Santa Lucia Rockhounds.
     The Santa Lucia Rockhounds of Paso Robles, California has an ongoing display located in the Paso Robles Area Pioneer Museum. Jeanne Lehir and Frank Imhoff are the curators of the exhibit and do a fine job of updating it about twice a year.
     The exhibit was the brainchild of Bob Mount, who was also the founder of the Santa Lucia Rockhounds. Some Indian artifacts are also on display, but the main theme is mining and mineral. Among the most studied are the maps plotting historical mines in the area, particularly the gold mining that took place in this area. Local teachers like to show the means by which gold was separated from dirt. They also point out the many minerals to be found locally.
     The Pioneer Museum is located on Riverside, just south of the Mid-State Fairgrounds. Santa Lucia Rockhounds annual show takes place the third weekend of September on the grassy area, adjacent to the Museum. Many Rockhounds have attended our show and spent time at the exhibit.
     To get there from the north, take the Highway 46 turnoff, turn right, go to the next street (which is Riverside), turn left and you can't miss it; from Bakersfield, take highway 46 to Riverside turn left and you are there. From the south take the Bakersfield turn off, turn left to Riverside, turn left and the museum will be on your left.
     COME SEE US. The museum hours are Thursday, Friday, Saturday and Sunday from 1:00pm to 4:00pm. Admission is free.
          Via CFMS Newsletter, January 1998.

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April 1956 - BRITTINGHAM (Ventura Jr College Geology professor) STUDENTS MAKE RARE DISCOVERY.
     Ventura College sophomore students Eugene Nicholas and Blanch Nelson discovered the fossil of a rare bird recently. The find was made in the rubble of a landslide in Balcom Canyon (nearer Santa Paula than Moorpark). VMGS has made many trips into this area and found many fish fossils.
     (Ed. Note: This fossil location is on private property, l998.)

          Inez Shakman,
          Historian.

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INTERESTING MINING FACTS.

• Television sets contain more than 35 different metals.
• More than 1/3 of all the gold which has ever been mined (1.1 billion troy ounces) is in various government vaults.
• Each of the many brilliant colors seen in fireworks displays is due to the presence of a particular metal.
• One of the oldest mining locations in the world is reputed to be Timna Valley in Israel, where copper has been mined since 4000 B.C.
• In the United States, gold bearing ore usually averages 0.1 troy ounces of gold per ton of ore.
• Face masks that astronauts wear are gold coated to protect them from the sun's fierce radiation.
• It takes 42 different minerals to make a telephone handset.
• Gold mining in South Africa has exceeded 12,000 feet. Many mines are so deep, exposed rock often explodes due to intense pressure from the rock above.
• Roman soldiers were paid in part with a salt ration called "salarium argentum." This is where the term "salary" comes from.
• The U.S. contains over 1/5 of the world's lead reserves, but 90% of the domestic lead that is mined comes from an area in southern Missouri.
• Tin is so important to our industrial society, the U.S. has established a five year stockpile. It is the largest strategic stockpile of any non-fuel mineral.
• Only 5% of the titanium produced is used to make metal. 96% of the titanium processed is used to make white paint or pigment.

     Reprinted from CGMS NEWS from National Energy Foundation,
     Via CFMS Newsletter, May 1996.

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February.

FOSSIL IMPRINTS.
     Here is a brief outline of the tools useful in collecting and working with fossils in the field.
     Sometimes in collecting fragile specimens, we have to remind ourselves when we see it is impossible to get a specimen out, not to destroy it. It is better to leave it until a later date, until we can get the proper tools, or conditions are such that we have a good chance of getting the specimen out in reasonably good condition. We don't want it said that we destroyed in five minutes what nature preserved for millions of years.
     Field tools vary with each collector and with the material being collected. The usual basic tools are:

• A prospector's pick for light digging and hammering.
• A brush to clean around the specimen being worked.
• A screwdriver for probing and prying small loose material from around a specimen.
• One wide and one narrow chisel for working a channel around specimens in hard rock.
• A center punch or a heavy-duty scratch awl (with the shank through the handle so it can be pounded) is sometimes good to remove excessive matrix.
• Fast-drying glue for use when specimens are found broken. It usually is more satisfactory to repair specimens in the field to keep them in line, so as not to have a jigsaw puzzle to work at home.
• A temporary preservative for fragile specimens. There is such a variety of preservatives that it may be best to have a special article on them, so send in your method of preserving specimens. A few are diluted shellac, plastic spray, gum tragacanth, dissolved cellulose, and clear fingernail polish.
• Labels. The value of a fossil is in knowing and keeping track of the location and formation or layer in which the specimen was collected. Be sure to label all specimens.
• A carrying bag for both tools and specimens. Tools should not be carried in the same compartment as the specimens. Besides damaging the specimens, the tools will always be on the bottom when needed, especially when walking a formation. We find that an army surplus ammunition bag for the specimens keeps the load equalized between front and back, and a surplus army belt for tools is very satisfactory. Wires can be bent to hold all types of tools. Small bags of all sizes and shapes are also available that can be fastened on the belt. Special tools or equipment can be placed in separate bags, then, when needed for a particular type of collecting, any combination can be selected readily and fastened to the belt.
• A spatula is very good for splitting light diatomaceous earth when collecting fish or plant imprints. (When splitting shales and diatomaceous earth, look for dark lines or spots on the edge, and split along the bedding plain at this point if possible.)
• Screens of various sizes of mesh, depending on what is being collected, are very useful when collecting in sandy material. If collecting in a sandy bank, it is sometimes best to work under the layer containing the specimens, letting the material drop free, then sorting it for specimens.

     This list of tools will get you by most types of fossil collecting, but you will be missing half the fun if you don't have a 10x or 15x hand lens to observe the details and to look for microfossils.
          By Bruno Benson,
          Gems & Minerals,
          May 1964.

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March.

A MOUNT FOR REALLY SMALL SPECIMENS By B. L. Benson, Ventura Gem and Mineral Society.
     If your specialty is micro-fossils or very small single crystals, here's a mount you will find most useful.
     My specialty is micro-fossils and shells, most of them far too small to mount in the usual micromount boxes. In order to display and catalog specimens properly, a mount had to be devised that was easy to use, that permitted proper labeling and cataloging and that allowed proper visual access to the specimens through the microscope.
     The pictures illustrating this article show the results of my efforts. Basically these mounts are simple and made from easily obtainable materials. All that is needed are some standard 25x75 mm (1" x 3") microscope cover glasses, some black paper, a little thick art board, some stiff paper for the back and a little gummed paper tape.

The upper picture shows B. L. Benson's mounting method for his microfossils. You are looking right down into the mount through the cover glass. Below are the three basic parts of the mount: the art board spacer with the hole, the black mounting paper, and the stiff white back cover.

Just some of the variety of holes that can be cut or punched into the art board for making special mounts.

     The mounts are like a sandwich. Starting from the bottom is the stiff white paper for a backing, the black paper on which the specimens are mounted, the art board (which should be about 3/32" or 1/16" thick) with a proper hole cut into it and, on top of the whole, a microscope cover glass. After mounting the specimens in the recess that the art board provides the whole thing is held together with gummed paper tape that laps the coverglass on top by about 1/8" and wraps around to the back to cover one-half or more of the bottom.
     The hardest job in making the mounts is cutting the hole in the art board. This job can be done with a sharp knife, razor blade or an art or hobby knife such as the Xacto. Mounting holes can be varied in size and position on the board as the illustration shows. Round holes can also be made easily with a washer cutter like those used by garage men to cut holes in gaskets. You will note that all of the holes are either off center or cut with ample white space around them. This leaves room for labeling with India ink and a quill pen. By labeling directly on the art board the label is completely protected once the cover glass is in place.
     You will also note that one of the mounts is divided into numbered squares. These squares can be ruled separately with white ink or, if you have the equipment available, a large copy, in the same proportion as you want the finished backing, can be ruled and then photographed down to size. This gives you a negative from which you can print as many backs as you need. The ruled back in the picture was made photographically. It is not necessary, of course, to use black backgrounds for the specimens. Any color or white can be used according to the requirements of the specimens to be mounted.
     As for mounting specimens, I use a method that serves me very well for the extremely small and light fossil and shell specimens that I collect. Before mounting the specimens I coat the black paper with gum tragacanth. This can be purchased in powder form from any drug store. You mix the powder with water. Don't mix too much as the gum swells (even more than rice). The whole square or hole can be filled with the liquid gum and when it dries there will be only a thin coating on the bottom of the slide.
     To mount a specimen just moisten the space that is to receive it with water and place the specimen in the desired position. To remove the specimen, just moisten it with water (provided it is not water soluble. Ed.), wait a second for the gum to soften, and then remove.
     To handle the small, light specimens I use a 00 sable brush. Just moisten the brush with water and touch it to the specimen which will then stick to the brush. After spotting the specimen in position the brush can be slid away from it easily.
     This mounting method is most useful for small, light specimens that have little thickness. However, the artboard spacer with the hole can be made as thick as desired to accommodate thicker specimens. Beside using them for micro-fossils they could readily be used for small crystals, powdery minerals, flake gold, sand, and specimens of this order. Also, the black paper and the cover paper on the back could be omitted and both sides covered with a microscope cover glass so that the entire mount would be transparent or translucent. This might be useful for specimens that should be lighted from below.
          GEMS & MINERALS,
          May 1954.

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MORE ON THE SMALL MICROMOUNT.
     B. L. Benson who supplied the material for A Mount for Really Small Specimens (G&M, May '54.) writes to give the following additional information on using the powdered gum tragacanth as an adhesive.
     Says Mr. Benson, "Mix the powdered gum tragacanth with hot water and add a drop of 5 % solution of formaldehyde or a drop of sulphuric acid, to prevent fungus growth, and a little glycerine to prevent cracking. The glycerine is not too important as it (the gum) generally cracks at the edge or thick parts. "Cores (for the cardboard spacers) can be drilled by clamping a stack of slides between boards and drilling through the boards to keep the cardboard from tearing. They can also be stamped out on a printing press which is the method we use and which is a little more expensive, but we help with the press work which cuts down the cost."
          Via Gems & Minerals,
          July 1954.

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April.

"THE JADES: COLORS AND CONTROVERSIES" By Lyle G. Gable.
     Jade and the color green are so inexorably linked that many people believe all jade to be green. Theoretically, pure jade, both nephrite and jadeite, should be white. Metallic salts in the form of oxides and silicates present, either alone or in combinations, and in varying degrees, are responsible for the vast array of colors, hues, shades, tints and tones, including multi-colors possible in jade. In rare instances, four or five colors may appear in a single stone. The green of jadeite is produced by chromium, the green of nephrite by iron. The degree of coloring agent present is presumed to determine the intensity of the color, a supposition partially refuted by the occasional occurrence of near-white nephrite with a high iron content.
     That jade has a wide range of colors is not in dispute, but opinions differ as to whether jadeite or nephrite has the greater range. Gerald Hamrich writes in The Handbook of Jade that the color range of jadeite exceeds that of nephrite. Judith Moorhouse contends in Collecting Oriental Antiques that the range (of color) in nephrite is greater. While near-whites and off-whites are not extremely rare, a true pure-white jade is rare. Unusual jade colors such as red, lavender, blue, mauve and purple are acknowledged, but the existence of pink jade is very much in doubt. Of twenty books, in whole or in part, which treat jade and its colors, eight list pink as a color for either jadeite, nephrite or both. Joan Hartman in Chinese Jade of Five Centuries concludes pink jade is non-existent, having never found even one example in the course of her research,. Richard Gump in Jade: Stone of Heaven, postulates the occurrence of pink jade and includes a color plate of what supposedly is a pink nephrite cup. A few years ago on a visit to the Norton Gallery in West Palm Beach, I may have seen a patch of pink jade. I am sure I saw a spot of pink on a water cup in the Chinese collection. The collection catalog designated the area a pinkish blush, but only tentatively identified the cup as Burmese jadeite.
     While it is probable that I will remain uncertain as to the existence of pink jade, it is even more probable that I will continue to hear someone exclaim, "But I thought jade was always green!"
          From Jax Gems 8/95,
          via AFMS Newsletter 2/98,
          (Honorable Mention in the 1996 AFMS Adult Article contest.
          Via CFMS Newsletter - April 1998.

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June.

GEODES.
     When lava is rapidly brought to the earth's surface, the reduced pressure causes the contained gases to expand, forming cavities. Later solutions moving through the rock will deposit minerals in the open spaces, leaving mineral lined cavities.
     Chalcedony is a fine grained quartz and is the most common geode forming mineral. Quartz deposited in concentric layers as agate, it may completely fill or partially fill the cavity. If only partially filled, crystals of quartz may project into the hollow center of a rock mass.
     Crystals found in the cavities may be colorless quartz, or amethyst, but rarely other crystals of gem minerals. Geodes are not confined to volcanic rocks, but also are found in cavities in some sedimentary rocks. These may contain gem materials too.
          From Michigan Gem News,
          via Conglomerate 5/92,
          via Drywasher's Gazette 6/98.

Table of Contents.

July.

THE BIGGEST, THE BEST, AND THE MOST GARGANTUAN.
     The Largest Gold Nugget ever found was called the Holterman Nugget. It was found in Australia on October 19, 1872 and weighed 7,560 ounces. That's 472 and a half pounds my friends. I could make a couple of rings out of that. And maybe even a bangle to spare.
     The Largest silver nugget weighed 2,750 lbs. troy. It was discovered in Sonora, Mexico, and was "appropriated" by the Spanish government before 1821. I looked up the word appropriate in the dictionary to see if they felt the same about the word as I did. Here are some definitions. Steal, filch, lift, nab, pilfer, pillage, swipe, and thieve.
     The Largest Pearl, for you pearl lovers, weighs 14 lbs., 1 oz. It is 9 and a half inches long by 5 and a half inches in diameter. It was found in Palawan, Philippines, on May 7th, 1934 inside the shell of a giant clam. It presently resides in a San Francisco bank vault and was worth $4,080,000 as of July, 1971. It is called the Pearl of Lao-tze.
     Opals anyone? How about one found in Andamooka, South Australia, in January 1970. It weighs 34,215 carats and was unearthed by a bulldozer.
     There is a Topaz out there that weighs 21,327 carats. Light blue in color, with 221 facets, it's called the Brazilian Princess. It was exhibited at the Smithsonian in 1978 and was then worth $1,066,350.
     Want something from the good old U S of A. How about a turquoise weighing 218 lbs., found in Riverside County, California, on January 17, 1975.
     Jade? Well, how about a boulder size piece found in British Columbia in 1977. It weighs 63,307 lbs.
     Okay. By a show of hands... how many of you want to know about marble? I know, I know. What has marble got to do with jewelry? Well, fact is, I'm thinking of making up some marble jewelry next year, and that justifies this little bit of info. Largest single slab ever found weighed 100.8 tons. It was quarried in Yule, Colorado, and a piece of this slab was cut for the coping stone on the Tomb of the Unknown Soldier in Arlington National Cemetery in Virginia.
     The largest Sapphire weighed 2,302 carats. It was found in Australia circa 1935, and was carved into the shape of the head of President Abraham Lincoln. Another black star sapphire weighing 2,097 carats was carved into a bust of General Dwight D. Eisenhower, circa 1954.
     Now... the largest of gemstones ever found in recorded history... a 520,000 carat aquamarine found in Brazil in 1910. It yielded 200,000 carats of gem quality cut stones.
     The rarest... there are only four of these stones in the world. It is a pale mauve gem known as Taaffeite. They were first discovered in Dublin, and the largest one weighs 0.84 carats.
          By Benjamin Mark,
          from The Slate March 1997,
          via AFMS NEWSLETTER 12/97-l/98.

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A LITTLE ABOUT PETRIFICATION.
     Have you ever wondered how petrification occurs? How does wood turn into stone? In so far as I can tell there are several events that occur in the process of petrification.
     Aside from the fact that the trees must first grow to provide the wood, the first step in the process of petrification is burial. The wood must be deeply buried either while still standing or soon after falling in order to prevent its destruction by the activity of ants, beetles, termites, and fungi. The environment in which the wood is buried must also be anoxia (without oxygen) otherwise micro-organisms would soon destroy the wood.
     The matrix encapsulating the deeply buried wood must be rather firm in the sense that it not be too plastic. A thick mud would not be stable enough to maintain the shape of the wood through the vagaries of time. Instead the matrix would have to be rather like a porous concrete or consolidated sand. The porosity is important because porosity allows the introduction of water.
     Once the wood is deeply buried in a consolidated, porous matrix in an anoxic environment it can only be transformed from wood to stone if quartz and water are present under the right conditions. No quartz, no water, no petrified wood.
     Fortunately, quartz is a common and abundant mineral, and even the deserts have their days in the rain. And as the fallen rain passes down through the ground, it picks up and carries a little quartz dissolved in its waters. This solution then permeates the buried wood. Now the miracle happens. A little wood dissolved into the water and a little quartz is deposited in its place; and the water moves on its way carrying away a little carbon, leaving behind a little quartz.
     The slow process of removing organic material while depositing quartz may take thousands of years to reach completion. In fact, petrification may not reach completion before the favorable conditions end.
     If you have collected petrified wood in the field you will know first hand that not all specimens are the same. The most sought-after petrified wood are specimens in which the process went to completion leaving behind highly agatized or opalized wood. These specimens can be sawed and the sawed ends given a mirror polish to reveal the beauty of the specimen. Specimens too small for sawing are tumbled to mirror finishes which are highly attractive.
     Wood that was not agatized or opalized may be shunned by collectors that fail to see the rugged beauty of the uncut, unpolished specimens. Other collectors favor these exquisite specimens as fossils of a bygone age and as natural works of art wrought by nature and not the hand of man.
     Believe it or not, some portions of a specimen may be preserved as the original wood while other portions of the same specimen are lignified or petrified to various degrees. While the rockhound may not appreciate these specimens, scientists may rejoice over the intact wood for it may reveal through their methods the ancestry and biology of the tree which otherwise they could never behold.
          By Michael J. Papay,
          from Rockhound Roundup Nov 94,
          Via The Glacial Drifter Feb. 98.

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