The Petoskey Stone - Oakland County Earth Science Club
Transcription
The Petoskey Stone - Oakland County Earth Science Club
The Petoskey Stone page 4 March "January" "February" "" "April"County Earth Science Club Oakland The Petoskey Stone January 2011 www.OCESC.com Geological Timescale gets new Period Club Meeting January 5th 7:30 Board Members meet at 6:15 If January comes, can April be far behind? Not with preparations for the April auction ! We're looking for members, who can help us sort, wrap, price or organize specimens for the April auction. We will meet on Friday afternoons at 1:00, beginning January 21. If you haven't done this before, come on by. It's a good way to learn about rocks and minerals. -- Katherine Van Hoy DUES DUES DUES YES, it is that time of the year when yearly dues are due. The fee is $20.00, with no extra charges. I will be collecting them at the January meeting so please don't make me run after you. I'm getting too old. See you, JANUARY 5th. Eleanor SILVER CLASS Delayed Silver Class was to begin soon, but Eleanor Snyder has unfortunately broken her ankle, and must heal before she can teach the class. Our best wishes for a fast recovery Eleanor! --Laura Sheffer (Editor’s note: The Ediacaran Period status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. This extract’s complete 2004 article link can be found at www.amfed.org, under “In the News” links.) The Ediacaran Period covers some 50 million years of ancient time on our planet from 600 million years ago to about 542 million years ago. It officially becomes part of the Neoproterozoic, when multi-celled life forms started to take hold on Earth. However, Russian geologists are unhappy their own title - the Vendian - which was coined in 1952, was not chosen. The decision was taken after a fifteen-year long period of consideration by expert geologists. "There's always been a recognition that the last part of the Precambrian is a special time before the first shelled animals, when there are these weird, mesh-like creatures of uncertain affinity," Professor Jim Ogg, secretary-general of the International Commission on Stratigraphy (ICS), told BBC News Online. “Now it’s part of the official timescale." The Petoskey Stone Upcoming Events (events can be found at www.rockngem.com or www.amfed.org/mwf/Calendar/) For detailed information, please visit individual club’s website. OCES Club members Silversmith class- delayed until further notice. Eleanor will make an announcement at the January meeting. 2011 Refreshments Jan. Feb. Phyllis Keene, Lynnette West, Kathy --Mar. April May June Banquet-Potluck Sept. K. Van Hoy, E. Snyder, D. &L. Whitehead Oct. Rose Woerner, Chris Shull Nov. Paulette Barterian, Linda Whitehead Dec. Club Banquet-everyone bring a dish 2011 Programs Jan. Chuck Miller, ‘The Rock Cycle’ Feb. Mar. April Silent Auction May June -Sept. --How the Earth Formed- Great Lakes Oct. – Alps – How the Earth Was Formed Nov. Club Member Swap/Sale Dec. --Banquet (each month needs two volunteers –please consider) --Betty Cockerham, Program Chair ***** January Birthdays ***** 1 JACKIE MIDTGARD 6 GEORGE MATYAS 10 JANE GUNTERMAN 10 JIM RIVES 12 ROSE SEIBERT 26 LAURIE WILKINS “People find life entirely too time-consuming.” Stanislaw J. Lec, Unkempt Thoughts Photo: Lt. Elizabeth Crapo, NOAA Corps Interesting Sites to Visit: The USGS (United States Geological Survey) has a number of educational and interesting materials at their website. One in particular, http://geomaps.wr.usgs.gov/parks/rxmin/, has a nice introduction to general geology. Charts, color pictures, and links to more in-depth information is available. The Vug website, http://www.the-vug.com/ is a commercial site, but has a lot of information, pictures, show info, etc. National Geographic Magazine’s site always has interesting items, especially on the science page: http://science.nationalgeographic.com/science/ The Petoskey Stone OCES BOARD MEETING DECEMBER 8, 2010: No Board Meeting was held. OCES GENERAL MEMBERSHIP MEETING, DECEMBER 8, 2010: The meeting started with grace being said and followed by a delicious buffet dinner provided by members with the club providing chicken and ham. A BIG THANK YOU to Nancy Pfauth and her committee for all of their hard work! After the dinner, the meeting was called to order at 7:45 pm by President Dan Woerner. Both the Treasurer’s and the Minutes were approved. Leon Pearson stated that since the By-Laws changes had already been read twice and published once, they were ready to be approved. Motion to approve By-Law changes was made and approved by membership. Cathy Roller gave the Oath of Office to the new Board members: Bob Albertson, Nancy Mathura, Nancy Pfauth, Tom Pierson and Roberta Thomas. Their terms will run for three years. Life Memberships were given to Kathryn Van Hoy, Eleanor Snyder, Barb and Tom Pierson and Phyllis Keene. CONGRATULATIONS! Tony West will be going out to Oregon for a field trip and asks that interested members contact him. Points of interest include Hampton Butte and Davis Creek for obsidian and petrified wood. Linda and Dave Whitehead passed through Henderson, North Carolina and said that the museum was worth the trip. Eleanor has name tags for all of our new members. Rose Woerner announced that gem trees will be the kid’s project in January and passed around a sample tree. Jim and Pat Rives thanked everyone again for the great food. The meeting was adjourned at 8:10 pm. Respectfully submitted, Chris Shull, Secretary. HOW TO OPEN A GEODE ( a continuation of the Junior Activities article on the next page) There are 3 main ways to open a geode. 1. Find someone with a “geode-cracker”. 2. Cut it in half with a diamond or masonary saw. 3. Strike it with a hammer and chisel - the most common way. But don’t just swing wildly. Small geodes will crush easily. a. If the selected geode feels light for its size, it probably has an inside pocket which may be lined with crystals. b. Wear safety glasses and gloves. c. If the geode is big enough, use a chisel to gently score all along the circumference. d. Then put the geode in an old sock and put the chisel in one of the score marks and tap gently in order to not crush the geode. e. If the geode does not break, tap harder. Use the minimum of force necessary to open it. f. The sock will keep the pieces from flying into eyes or getting lost. g. If the geode is not big enough to score with a chisel, put the geode in an old sock and gently tap it. Again, tap harder if it does not break, but use as little force as possible in order to not destroy the crystals that may be inside h. Be aware that the geode may be totally filled in or simply a solid concretion. Not all apparent geodes will have desirable things inside. Sources: GEODES-Nature’s Treasures, by Brad L Cross and June Culp Zeitner, Gem Guide Book Co., Baldwin Park, CA. 2006. 1001 Questions Answered About the Mineral Kingdom, by Richard M Pearl, Grosset & Dunlap, New York NY 1959. JUNIOR ACTIVITES by Michele Yamanaka, interim MWF Junior Activities Chairman Written for the November 2010 Strata Data and the December 2010 MWF News. HIDDEN BEAUTY: A Look Inside GEODES WHAT IS A GEODE? The word geode comes from the Greek word geoides, which means “earth-like”. Geodes are earth-shaped (as in the planet Earth, therefore somewhat round) natural, organic objects which are or have been hollow. Usually it has an outer shell of chalcedony, which is in the quartz family. The interior of the object may be lined with crystals, most often quartz, which point toward the center. There may be secondary mineral growth. It should show concentric inward growth and may even be completely filled in. Then it is called a nodule. HOW DO GEODES FORM? Scientists are still investigating geodes and there are different ideas about where and how they form. The information shared here is based on the recently published book, GEODES-Nature’s Treasures, by Brad L Cross and June Culp Zeitner, Gem Guide Book Co., Baldwin Park, CA. 2006. Geodes form in sedimentary rock and in igneous rock. Sedimentary geodes are less round than igneous geodes and contain more calcium carbonate. Some of the possible origins of geodes are: gas bubbles in volcanic rock in which silica-rich solutions fill in the bubble area expansion of fossil shell and replacement of calcite by silica a concretion formed by anhydrite or calcite that is replaced by silica and re-crystallization of calcite silica gel filling in a cavity left in sediment by marine life such as sponges or clams There is no “one” way that geodes seem to have formed. They all have in common that: 1. the exterior surface of the geode is harder and tougher than the rock in which it is found; 2. layers grow inward toward a central area that started as a cavity. Some geodes are fossil-shaped; some are quartz paramorphs after coral or shells. They can be tiny or several feet across. The outside and inside can be any color of the rainbow. The crystal formations inside can be welldefined crystal shapes, bubbly, grape-like, or stalagtitic. Many kinds of minerals, such as quartz, calcite, pyrite, selenite, barite, malachite, fluorite, sulfur, opal and more, can be found inside geodes, including petroleum, water and gas. The most exciting thing about geodes is that the outside gives no clue about what is inside. It is an amazing experience to be the first to see what treasures may be inside! (see previous page for ‘how to open a geode’ a continuation of this article from the MWF newsletter) The Petoskey Stone Lapis Lazuli Extract of an article from The Living Stones, Nov. 2010, credited to ICA Gem Bureau, Idar-Oberstein Lapis lazuli is regarded by many people around the world as the stone of friendship and truth. The blue stone is said to encourage harmony in relationships and help its wearer to be authentic and give his or her opinion openly. Lapis lazuli is an opaque rock that mainly consists of diopside and lazurite. It came into being millions of years ago during the metamorphosis of lime to marble, Uncut, lapis lazuli is mat and of a deep, dark blue colour, often with golden inclusions and whitish marble veins. The small inclusions with their golden shimmer, which give the stone the magic of a starry sky, are not of gold as people used to think, but of pyrites. Their cause is iron. The blue colour comes from the sulphur content of the lazurite and may range from pure ultramarine to a lighter blue. At between 5 and 6 on the Mohs scale, this stone is among the less hard gemstones. The worth of this stone to the world of art is immeasurable, for the ultramarine of the Old Masters is nothing other than genuine lapis lazuli. Ground up into a powderand stirred up together with binding agents, the marble-like gemstone can be used to manufacture radiant blue watercolours, tempera or oil paints. Before the year 1834, when it became possible to produce this colour synthetically, the only ultramarine available was that valuable substance made from genuine lapis lazuli that shines out at us from many works of art today. Many pictures of the Madonna, for example, were created using this paint. 6