science

How we add to the sum of the world’s knowledge.

Special Exhibits 2017

KANSAS CITY GEM SHOW SPRING 2017 FEATURE EXHIBIT

ROCK ART –Stone Quilt Design; Susan Judy; Denver, CO and WKP Accent Tables; Bill Peterson; Boulder, CO
Colorado artists Judy and Bill have brought some of their creations to the Kansas City Show.  Judy inlays natural materials in a stone mosaic to create pictures and Bill uses natural materials to create tables.

INVITATIONAL EXHIBITS (more…)

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Collagen Found in Dinosaur Bones

Paleontologists at the University of Toronto just found collagen in a 195 million year old fossil. This makes it the oldest protein that has ever been found. Previously, the oldest protein sample was only 80 million years old (it was also collagen, from a dinosaur bone). They also found hematite crystals in the fossil, which possibly came from the blood. The dinosaur was a Lufengosaurus that lived in Yunnan Province, China.

Some other paleontologists didn’t like the new, non-invasive methods that the team used used to identify the collagen, but other scientists thought the methods were fine. Read the whole article here https://cen.acs.org/articles/95/i6/Collagen-found-195-million-year.html and let me know what you think.

Gem Show Pictures Fall 2016

KCI Expo Center outside building

The Gem and Mineral Show was once again at the KCI Expo Center

selling rocks and books convention customers

The view from behind the Association booth.

yellow keokuk geode

This yellow geode is from Keokuk in St. Francisville. They call it “Lemoness”.

crinoid Scyphocrinites elegans fossil from Morocco

This huge crinoid (Scyphocrinites elegans) fossil is from Morocco.

kansas fossils

There were also fossils from Kansas available.

tiny beads in tubes

Plenty of beads for sale at the show.

fossilized starfish britlestar ophiura morocco

Fossil Brittle Star from Morocco, sold by Schooler’s Minerals. Fun fact: a brittle star is from the class Ophiurida and starfish are from the class Asteroidea, so they are not really related to starfish at all.

official-apron

Bob models an official Association apron and holds a pufferfish.

pufferfish

The preserved pufferfish close up. It is hollow and light as a feather. I don’t think anyone bought it so it will be for sale again in March.

books about minerals and gem cutting for sale

Some of the mineral, fossil, and jewelry-related books we had for sale this year.

carved mineral skulls

Carved skulls made of semi-precious minerals.

dino agate.JPG

Is this a giant dinosaur showing off a giant agate, or a very small dinosaur with a tiny agate?

potter with pots and bowls oklahoma dirt shirt

Martin selling pottery that he made

men packing items for storage

Everything is packed up into our big blue cube until the next show.

Congratulations Scholarship Winners

Every year, the Midwest Federation offers scholarships to students studying geology or earth science related fields at the college or post-graduate level. If you purchased anything at the Scholarship Auction at the March Gem & Mineral Show in Kansas City, or at the auction at the Association Picnic in August, then you contributed to these scholarships. Thank you!

Dr. William S. Cordua is a retired professor from the University of Wisconsin. Dr. Cordua is the chair of the Geology committee of the Midwest Federation of Mineralogical and Geological Societies. Dr. Cordua has chosen the two students:

Ms. Kari Wolfe is pursuing her Masters degree in Nitrate Pollution in Tile Water in Dead Zones in the Gulf of Mexico, through the University of Wisconsin in Minneapolis.

Ms. Colleen Hoffman is pursuing her Ph.D. degree in Mineralogy and Biogeochemistry of Deep Sea Hydrothermal Vents, through the University of Wisconsin in Minneapolis.

For more information about the scholarships, including how to apply: http://www.amfed.org/mwf/federation/scholarships.html

How Amethyst Cathedrals are Formed

purple amethyst cathedral in a museum with other minerals

Amethyst cathedral at the Sutton Museum. Photo by Stephanie Reed

Article by Dr. Bill Cordua, University of Wisconsin-River Falls

Have you ever been to a show and seen enormous amethyst geodes or crystals 3-5 feet or more in height? The tubular geodes are lined with deep purple gemmy amethyst crystals. How do such wonders form?

These excellent geodes come from a region along the Brazil-Uruguay border. The genesis of deposits on the Brazil side of the border has recently been extensively researched by an international team of geochemists lead by H. Albert Gilg of Techniche University Munchen in Germany (Gilg, et. al., 2003). The geodes are mined from several lava flows belonging to the Parana Continental Flood Basalt Province. This was one of the largest outpourings of basalt lava known. An estimated 800,000 cubic kilometers of lava extruded over an 11 million year time span. For comparison, this would be enough to cover Minnesota with a pile of basalt lava over 2 miles high. The lava outburst occurred as part of the opening of the South Atlantic Ocean during Cretaceous time about 130 million years ago. Of all these flows, however, only a few are known to host amethyst cathedral geodes.

Gilg et al. proposed a 2-stage model for their formation. In the first stage the large hollows form. This was caused as volcanic gases were released from certain lavas as they cooled. Not every lava has enough dissolved gas to form such big openings. As gas bubbles emerged from the congealing lava (much as bubbles emerge when beer or soda pop is poured) they coalesced as they rose. The lava was cooling fast too, and soon became so thick and sticky that bubbles quite rising and were trapped. The bulbous to tubular shapes thus point towards the top of the flow, a fact easily seen when the geodes are in place in the mines. These cavities, though, were empty of crystals.

The second stage was the formation of the amethyst, plus celadonite, calcite and gypsum fillings. An important clue to this event is the presence of small gas and liquid bubbles (called fluid inclusions) trapped within these minerals. These are samples of the mineral-forming liquids caught as the crystals grew. Fluid inclusions are treasure troves of information when studied with sophisticated instruments. Analyses of the fluid inclusions in the amethyst, calcite and gypsum show them to be filled with slightly salty water. This water had a temperature of no more than 100 degrees C, and possible less than 50 degrees C, during mineral formation. These cannot be fluids related to the magma that formed the lavas.

What was the source of these fluids? An amazing story unfolds from the radiometric dating of the minerals. The basalts formed about 130 million years ago, but the green celadonite, which makes up the rinds of the geodes, formed about 70 million years ago. For 60 million years these enormous cavities sat empty of crystals. Trace element data from the fluid inclusions gives another important clue to the source of the mineral-forming fluid. Below the lavas is a large aquifer (the Botucatu aquifer) filled with ground water that closely resembles the fluid inclusion liquids. Uplift and tilting of the area about 70 million years ago would force water out of the aquifer into the porous areas of the overlying lava. In the lava flow these waters would have found volcanic glass. Glass breaks down over geologic time and makes silica and other chemicals available in a form that is readily soluble in water soaking through the rocks. The water carried these chemicals into the cavities, where the amethyst and other minerals grew due to cooling and pressure release.

The special combination of geologic circumstances, unfolding over millions of years, is not often duplicated. Understanding the process gives geologist tools to prospect more efficiently for these wonders.

Reference:
Gilg, H. et. al, 2003, “Genesis of amethyst geodes in basaltic rocks of the Serra Geral Formation (Ametista do Sul, Rio Grande do Sul, Brazil): a fluid inclusion, REE, oxygen, carbon, and Sr isotope study on basalt, quartz and calcite” Mineralium Deposita vol. 38, p. 1009-1025.

The Glacial Drifter 08/2011, The Gemrock 06/2015

Curb Showing Hayward Fault is Replaced

Hayward, California is the home of the Hayward Fault, which is a break in the Earth’s crust. Geologically speaking the Hayward Fault moves very fast. You can see that the tectonic plates are always moving when you look at the roads. Since it only moves a few millimeters a year, the roads and/or curbs don’t crack but instead gently wiggle apart at the seams.[*] See how this curb at Rose and Prospect has moved over time?

curb a few inches offset hayward fault

This is how the curb looked in 1974. It has already drifted several inches from where it was originally. Photo from http://www.geologyfieldtrips.com/haywardresidential.htm

hayward fault curb 2012 with people standing on top

This is how the curb looked in May 2012. See how far this piece has moved away? Photo by Andrew Alden at oaklandgeology.wordpress.com

If you want to go to California and see it for yourself, you are out of luck. The city has just replaced the curb. This is probably the first time that road work has made it into the New York Times. Read the article here: A Curb is Repaired and a Seismic Marker is Lost

[*]Note: Cracks in the road are not caused by plate tectonics. They are caused by thermal expansion/contraction, road salt, heavy trucks, and degredation of the road bed.

Labradorite

Labradorite has become a popular gemstone because of the unique iridescent play of color that many specimens exhibit.  Labradorite is a feldspar mineral of the plagioclase series that is most often found in mafic igneous rocks such as basalt, gabbro and norite.  Some specimens of labradorite exhibit a Schiller effect, which is a strong play of iridescent blue, green, red, orange, and yellow colors as shown in the photographs above. The Schiller effect is also seen in fire agate and mother of pearl. Labradorite is so well known for these spectacular displays of color that the phenomenon is known as “labradorescence.” Specimens with the highest quality labradorescence are often selected for use as gemstones. Labradorescence is not a display of colors reflected from the surface of a specimen. Instead, light enters the stone, strikes a twinning surface within the stone, and reflects from it. The color seen by the observer is the color of light reflected from that twinning surface. Different twinning surfaces within the stone reflect different colors of light. Light reflecting from different twinning surfaces in various parts of the stone can give the stone a multi-colored appearance.

Source: http://geology.com/gemstones/labradorite/

Minerals in Fireworks

The 4th of July fireworks that we saw last night would not be possible without minerals. Fireworks mainly contain gunpowder, which is a combination of charcoal, sulfur, and the mineral potassium nitrate. In order to create the pretty colors we are used to seeing in fireworks, mineral salts are added. This infographic from Compound Interest explains which mineral salts create which colors. If you go to the website, you can read a lot more about the chemistry of fireworks and a brief explanation of why different minerals make different colored flames.

I learned that blue fireworks are very difficult to produce because copper chloride breaks down at high temperatures, so they have to somehow keep the temperature hot enough to ignite but not so hot that the blue color vanishes. Thus, you almost never see purple fireworks because it is a combination of red and blue.

Weathering

Weathering is when rocks break down in place, that is, without moving the rock. This is usually done by water, but there are plenty of other physical and chemical processes that break down rocks without moving them. Physical weathering occurs when a tree root grows into a rock and breaks through, when a river cuts through a canyon, when particles carried by the wind abrade the rock, or during the process of frost wedging, which is when water fills a crack in a rock and freezes, then the ice expands and makes the crack deeper. Chemical weathering can be caused by acid rain or even regular rain, as minerals in the water weaken the rocks and make it easier for them to be eroded or broken later. Minerals can even react with chemicals in the air (such as iron and oxygen reacting to form rust, also known as iron oxide) or with other minerals nearby. Minerals are made of chemicals, after all, and there is nothing stopping them from reacting with one another.

There are a lot of interesting ways that minerals can change due to weathering, both physical and chemical. For example:

  • Limestone dissolves
  • Calcite dissolves
  • Gold may dissolve if manganese is present
  • Silver minerals can change to horn silver (cerargyrite) or dissolve
  • Feldspar changes to clay
  • Olivine and hornblende change to serpentine or chlorite
  • Pyrite changes to limonite and hematite
  • Rhodochrosite and rhodonite change to psilomelane or pyrolusite (manganese) minerals
  • Copper sulfide minerals change to malachite, azurite, cuprite, or metallic copper, or may dissolve entirely
  • Some copper minerals become partly limonite

Adapted from an article in Cycad, Flint Chips, Osage Hills Gems 11/1992

Characterization of Green Amber

silver ring with oval green amber

Green amber ring owned by Stephanie. It has nothing to do with this article. Photo by Stephanie Reed

David highly recommends this article on green amber from Gems & Gemology, 2009. Here is the abstract.

Ahmadjan Abduriyim, Hideaki Kimura, Yukihiro Yokoyama, Hiroyuki Nakazono, Masao Wakatsuki, Tadashi Shimizu, Masataka Tansho, and Shinobu Ohki

Abstract: A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market. It is produced by treating natural resin (amber or copal) with heat and pressure in two stages in an autoclave. Differences in molecular structure between untreated amber and copal as compared to treated “green amber” were studied by FTIR and 13C NMR spectroscopy, using powdered samples. Regardless of the starting material, the FTIR spectrum of “green amber” showed an amber pattern but with a characteristic small absorption feature at 820 cm-1. Solid-state 13C NMR spectroscopy of the treated material indicated a significantly lower volatile component than in the untreated natural resin, evidence that the treatment can actually “artificially age” copal. A new absorption observed near 179 ppm in the NMR spectra of all the treated samples also separated them from their natural-color counterparts.

To read the whole article, go here http://www.gia.edu/gems-gemology/fall-2009-green-amber-abduriyim and click on “Download PDF”.