The Ventura Gem & Mineral Society, Inc. (VGMS)
Gem, Mineral and Fossil Information 1997 Archive.
Table of Contents.
March.
LEGEND OF THE APACHE TEAR DROPS.
Apache Tear Drops is a legendary name given to these stones by Indians of the Apache tribe of Central Arizona.
The gateway to a great mineral district is a towering mountain with sheer cliffs that rises out of the desert floor, known today as Picket Post Mountain. As the legend goes, it was on this mountain that the Spaniards cornered a party of Apache warriors. To be captured meant to be a slave for life in the Spanish gold mines; to retreat meant a fall over the cliffs. The Indians chose death.
Later when the squaws came to gather the broken bodies of their brave warriors, a voice in the breeze whispered, "thy bitter tears shall be turned into beautiful stones, for I should not have made these cliffs so high."
So, today, if you should happen to be near Picket Post Mountain and a gentle breeze sounds like a sob from a broken heart, you may think it is only your imagination until you look down at the ground and see some Apache Tear Drops that were not there a moment ago.
Contributed by Florence Meisenheimer.
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Table of Contents.
April.
FOSSIL IMPRINTS by Bruno Benson.
The average fossil collector seldom knows about or collects microfossils, perhaps because they are a little harder to find or to remove from the matrix. Micro-organisms are the most abundant form of life and therefore should be the most abundant type of fossils. The variety of shapes and kinds seems endless. The best places to look for microfossils is in the thin, dark layers of sedimentary deposits; sampling of layers containing larger fossils is recommended.
Small bottles containing various kinds of acid are useful for testing calcareous shales, carbonate rocks, and for etching limestone surfaces. The acid most commonly used is a 10 per cent solution of hydrochloric acid. If the reaction is too severe, dilute the acid to 50 percent (acetic acid) or use formic acid, 1 part acid to 4 parts water; also, oxalic acid or phosphoric acid is good for gentler reaction.
The best procedure is to crush the calcareous shale to 2 or 3-inch pieces, then split them with a razor held in a window scraper, or with a single-edged blade held by hand. Examine the exposed surface with a hand lens. If a fossil is observed, test it with one of the acids. With a dropper, apply the acid to the specimen and surrounding area.
If the acid does not dissolve any of the specimen, and if the fossil is etched in relief --- that is, if a little of the area around the specimen has been dissolved --- immerse the rock in the solution that worked best in the test. When effervescence has ceased, pour off the neutral acid and add new acid. Repeat the process until the fossil is free. Wash the residue, then treat it as a regular microfossil. With the milder acids, care must be taken to keep the action going, or the solution will crystallize; then it is difficult to start again.
Working with acid should be done outdoors to allow the fumes to be carried away. Fumes are corrosive and may damage metal.
If the fossils are of the same material as the matrix, they are difficult to remove. Mark a large circle around the fossil for spotting easily, then trim with side cutters or pliers, and mount as preferred. This method will work on larger specimens, too, but do not crush; also more time and acid are needed.
Photographing Microfossils - When photographing microfossils, use glycerin on translucent specimens to bring out internal structure. For white specimens, use a water-soluble brown ink. Apply it with a small brush. When dry, rub the specimen lightly with a damp brush which will remove the ink from the ridges, leaving the brown ink in the cavities, thereby showing more details.
Black specimens can be whitened in varying degrees by using a two-bottle fume mixer. With it, ammonium chloride can be blown on the specimen in a thin film. The coating can be removed by simply blowing your breath across the specimen.
The fume mixer is made by tying two bottles together. Put hydrochloric acid in one, and ammonium hydrate in the other. A is the mouthpiece of two glass tubes that go down through the cork into the liquids. Tubes B expel the fumes; they go through the cork and are tied together. By blowing through mouthpiece A, the fumes of the two acids, HC1 and NH4OH, unite at outlet B and form a white sublimate of ammonium chloride on the specimen held at that point. Be extremely careful in handling all types of acid!
(This article by Bruno was first published in the Gems & Minerals August 1964 Magazine.)
Table of Contents.
September.
TYRANNOSAURUS REX LIVES AT VGMS MUSEUM!
Well a part of it anyway! We have a NEW ADDITION to the Museum, thanks to Bruno Benson, that no one has seen before. It wasn't even at our CFMS show! We have a Tyrannosaurus Rex foot, there is some discussion as to rather it is the right or left one!! Some say it was the only one left so it must be the left!! At any rate it is magnificent and if you haven't seen it, call Ray or Bruno to make a visit. It is about knee (our knees) high and about 12 to 16 inches across. The curator and his staff are looking to get a stand made for it.
We have some other new additions that we will feature in the next bulletin. They are both skulls and were on display at the CFMS show.
TYRANNOSAURUS REX - He was the last of the Deinodonts and was a massive, erect dinosaur with the largest head known among saurischians. Tyrannosaurus was 47 feet long, 18 feet tall, and weighed 8 to 10 tons. Its knee joint was 6 feet above ground; the claws on its hind feet were 6 to 8 inches long; its skull measured 51 inches from front to back; its teeth were serrate blades 3 to 6 inches long and an inch in width. The forefeet are unknown but, like those of earlier deinodonts, they probably had only two toes and were too small to be of much use, even in handling food.
We are tempted to picture the food of Tyrannosaurus in massive proportions to match his size. Actually, the great carnivore lived during latest Cretaceous times, when Diplodocus and Brachiosaurus had been extinct for 50,000,000 years and lesser sauropods were rare. The tyrant saurian's prey consisted of herbivorous reptiles 20 to 30 feet long that waded, swam, and walked on lowlands of western North America. What they lacked in bulk they made up in numbers. The tyrant seldom went hungry; he merely took more meals than his predecessor, Allosaurus.
TYRANNOSAURUS REX.
Information & Drawing Contributed by Bruno Benson,
via The Fossil Book.
Table of Contents.
NEW SMITHSONIAN GEOLOGY, GEM, AND MINERAL EXHIBIT HALL.
September 20, 1997 is the grand opening for the new Janet Annenberg Hooker Hall of Geology, Gems, and Minerals at the Museum of Natural History in Washington, D.C. The magnificent 45.52 carat Hope Diamond is one of the main attractions. The entire hall is designed to not only appeal to the professional geologist but also to the casual interested observer.
In addition to the National Gem Collection with hundreds of our best known cut-stone creations there is a gallery devoted to Minerals and Gems and a 1600 square foot mine showing how zinc, copper, lead and semiprecious gems are found. The Plate Tectonics Gallery has an impressive six foot globe minus the oceans which makes the various plates stand out dramatically. Throughout the entire $16 million Hall (financed almost entirely by private donations) there are countless opportunities with videos, historical exhibits, literature, etc. to satisfy the desires of nearly all visitors. The Museum of Natural History gem collection in New York is comparable but the total collection is only about half the size of the one in Washington.
If you are ever making a trip back to Washington it is very worthwhile to include a few days extra to visit the Smithsonion and other monuments in Washington. Of course, if desired, a visit to the Capitol and the White House can be included.
Contributed by Wayne Ehlers.
Table of Contents.
October/November.
MOSASAUR CO-HABITS WITH TYRANNOSAURUS REX AT MUSEUM.
Does that sound wild or what? They do, however, and are wonderful to visit! We featured Rex and his foot last month so this month we are introducing Mosasaurs. Bruno Benson, our curator, acquired the Mosasaur Skull which we had in time for the CFMS show. Hopefully you were able to see it there. He had a great display. Well - Good News! If you didn't see it at the show you can see it at the Museum. Just give Bruno or Ray a call and they will be proud to introduce you!
MOSASAUR.
Early accounts occasionally described plesiosaurs as "savage monsters of horrid mein." Actually they seem to have been sluggish, dull-witted creatures that threatened only the animals on which they customarily fed. Lurid adjectives apply more aptly to the great aquatic lizards known as mosasaurs.
Mosasaurs were bizarre reptiles, and their introduction to science was equally spectacular. In 1780, workmen discovered a petrified skull in a subterranean sandstone quarry under the Pietersberg (Peter's Mount) near the city of Maastricht, Holland. The men sent for an army surgeon and naturalist who had collected fossils from the quarry. He directed work so skillfully that the entire skeleton was removed.
Dr. Hofmann recognized the specimen's value, paid for removing it, and prepared it for exhibition. But land above the quarry was owned by one Canon Goddin, who went to court, won his case, and seized the fossil. Then in 1795, a French army besieged Maastricht, and so famous had the fossil become that the general in command told his gunners to spare the part of the city containing Canon Goddin's house. Suspecting the reason for this favor, Canon Goddin hid his specimen, trying to keep its location secret after the city surrendered. The French thereupon offered a reward--said to have been six hundred bottles of wine--for the specimen, and a band of thirsty grenadiers soon found it. Taken to Paris, it was described as a "primordial" whale, or "breathing fish," and then as "the Great Lizard of the Meuse," the river that flows past the Pietersberg. A British author translated this cumbersome term into the Latin Mosasaurus.
Mosasaurs ranged round the world during late Cretaceous epochs, reaching their zenith in seas that spread inland from the Atlantic Ocean and the Gulf of Mexico. The finest specimens come from chalk deposits of western Kansas, but the largest known species was a giant some 45 feet long whose jaws and teeth are found in greensand beds of New Jersey. Strangest member of the group was Globidens, of the southern United States and Europe. It apparently fed upon the sea bottom, where it grubbed for clams, snails, and other sluggish mollusks whose shells it crushed between bulbous teeth that had all but lost their once-sharp points.
The typical mosasaur, such as Tylosaurus of Kansas, was an active swimmer with a long body, flattened tail, and feet that had become broad, webbed paddles with well-developed toes. Bony plates covered the top of the head; neck, body, and tail were covered by lizardlike scales still preserved in a few carbonized fossils. Sclerotic rings strengthened the eyes, and the eardrum consisted of thick cartilage. The lower jaws, each armed with sixteen to eighteen sharp teeth, were connected by ligaments at the front and had double hinges behind. Like serpents, mosasaurs were able to drop their jaws and spread them widely in order to swallow oversized food.
Petrified stomach contents show that fish formed the chief food of mosasaurs. With lengths of 20 to 30 feet, they were the only vertebrates that could capture such forms as the "bulldog tarpon" (Portheus molossus), which weighed 600 to 800 pounds and was as dangerous as most reptiles. Since old, dull teeth dropped from the jaws and were replaced by new ones, mosasaurs never lacked weapons with which to attack rivals or prey.
Information & Drawing
contributed by Bruno Benson,
via The Fossil Book.
Table of Contents.
DID YOU KNOW? QUARTZ USE IN WATCHES.
Most of us have seen the term "quartz watch" but have not really known what it means. We do know that the watch is quite accurate, needs a battery, and does not need to be wound. One of the characteristics of quartz is that it vibrates at a constant rate of 32,768 times per second, and can be used to control the watch hand movements. The little battery energizes the quartz, the quartz vibrates at its set rate, and the movement does the rest. It is true that we use other crystals in the same way in other electronic gear such as computers, transmitters, telephones, etc.
Wayne Ehlers,
From the Tucson and San Diego GMS Newsletters.
Table of Contents.
December.
JASPER.
Jasper is in the silica group of minerals. The silica group is divided into crystalline quartz and amorphous rock which does not form crystals.
The name jasper applies to various forms of opaque chalcedony of richly colored rock consisting of interlocking crystals of quartz too small to see with the naked eye. Jasper is born of fire and ice, the impact of hot lava and cold rock. Most commonly the cold source rock is porphyry, a dark igneous rock that contains relatively large and conspicuous crystals in a fine grained mass. They melt while the other components of the rock remain solid. This produces a silica laden fluid that flows into the cracks of the porphyry where it quickly cools and crystallizes. It is the rapid cooling that prevents the growth of large crystals and thus promotes the formation of jasper. Jasper may also form in sedimentary parent rock, again with lava as the heating agent.
Jasper is frequently found near deposits of iron ore, and often it contains iron compounds and impurities. These impurities usually give a red and brown color to the jasper. There is also yellow and green jasper. Red, brown and yellow comes from iron oxides. The mossy green tones come from chlorites (minerals containing magnesium, aluminum, and silicone). It is rare if any one finds a single color jasper.
It is the cryptocrystalline structures of jasper, its density and hardness that enables the craftsmen to work jasper to a high polish.
From The Glacial Drifter 4/97,
via Florence Meisenheimer.
Table of Contents.
QUARTZSITE MARKERS SEPARATE DAKOTAS.
The boundary between North and South Dakota is the only border between two states marked every half mile with quartzsite markers. In 1890, the United States Congress appropriated $25,000 for the project. The markers, cut from a quartzite quarry at Sioux Falls, South Dakota, are seven feet tall and ten inches square, and are set three and a half feet into the ground. Surveyor Charles H. Bates placed 720 monuments along the boundary, only two of which could not be placed in precise locations because of rivers.
Bates placed the monuments in 1891 and 1892. The monuments were shipped to the border via railroad and Missouri River Steamboat.
The initial monument was placed where the borders of North Dakota and South Dakota and Minnesota touch, and the final monument (360 miles from the initial stone) was placed in August 1892 at the juncture of the North and South Dakota and Montana borders.
Bates jokes that he should be an honorary member of the Humane Society for having erected 720 "superb cattle-scratching posts".
Via Breccia 11/96 & Glacial Drifter 7/97,
via Florence Meisenheimer.
Table of Contents.
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