The Spring 2017 Gem and Mineral Show was very successful. The parking lot was filled to capacity and we made over $3000 for the scholarship fund. I think it helped that it was so cold on Saturday, because people wanted to do something indoors. Here are some of the highlights.
When you come to the show, don’t forget to enter the drawings for door prizes.
This hematite and magnetite specimen is from Patagonia, Argentina. Bruce got it at the Denver show and gave it to Sharon Penner. It’s about 4 inches long and pretty shiny.
In November 2016, we went to see Marv Dahmen’s collection of vintage Joplin/Tri-State mining equipment and minerals. He talked about it for 5 hours but there was never a dull moment. We managed to record some of it, although it was so long Stephanie and David ran out of space on their phones. Here are some photos.
Thank you Marv for inviting us on your property and into your home to see your amazing collection!
Rutile quartz is quartz that contains rutile inclusions. Rutile is made of titanium dioxide and usually forms long, thin needles. It is most commonly found in quartz, though it can also be found in sapphires. The inclusions are usually gold in color and can be seen in dense parallel fibers or as scattered needles. You can see both in this specimen.
This rutilated quartz sphere is smoky quartz with rutile inclusions from Minas Gerais, Brazil. It is on display at the Rice Museum in Hillsboro, Oregon near Portland, Oregon. If you are in the area, we highly recommend this museum.
Special guest article from Show-Me Rockhounds club members Dan and Connie Snow
Fairburn agates are a form of microcrystalline chalcedony, 100% silicon dioxide with a hardness of 6 ½ to 7 on the Mohs scale. They are also called fortification agates because of their banding. They were formed approximately 300 million years ago in an ancient limestone bed of an inland sea. To hunt Fairburn agates requires looking at every rock and turning many with a rock pick. It is strictly surface hunting no digging, mining, cracking or breaking rocks. The photos shown are exactly the way the agates were found, with no cutting, polishing or tumbling having been done.
Fairburn Agates found by Dan and Connie Snow. Collected from the Fairburn Agate beds of South Dakota and the Oglala National Grasslands in Nebraska.
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.
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.
Selenite is a type of gypsum that has a flat reflective surface, usually gray, clear, white, or amber. Red is an unusual color for selenite, but they do exist. It is very soft and can be scratched by a fingernail (2 on the Mohs scale). At our February meeting, two of the door prizes were these selenite crystals found by President David Reed. The amber one is from Lake Kanopolis in Kansas. The gray one is from Lake Wilson, which is also in Kansas. David went to Lake Wilson and put a small crystal in the mud. He returned 3 years later and found the large gray crystal.
One time David and Stephanie went to Kansas and found several selenite crystals somewhere near the dam at Lake Wilson. They were gray like this one pictured, but much smaller. On the April field trip to Marquette, some club members also found selenite crystals.