Minerals

SEPTARIAN NODULE

A cut and polished septarian nodule.  First photographed under white light, then short wave ultraviolet light.  It will be in the fluorescent mineral display at the 59th Gem & Mineral Show at the KCI Expo Center March 13th, 14th and 15th, 2020.

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Photographed by Dan Snow

 

 

 

November Waldo Library Display

Show-Me Rockhounds – show-off some of their activities and display specimens of rocks and minerals.  Credit for the display and arrangement goes to Steve.  He put together two very nice posters showing some club activities including wire wrapping, field trips and related photos of interest.  One poster asks it you might be a rockhound.  All specimens are from Steve’s and other members collections.  What a great variety!  Something for everyone.   Photos by Connie Snow

 

 

Door Prizes Spring 2018

Adult Door Prizes

DSC_2234#1 Pendant created by artist Marv Dahmen. Valued at $55 (I think it might be more valuable than that -ed.)
DSC_2229#2 Polychrome jasper from Madagascar. 6 1/2″ tall and weighing 5 1/2 lb. Valued at $100
DSC_2219#3 Large trilobite from Morocco. 16″ long. Valued at $250

Kids’ Door Prizes

DSC_2225#1 Bismuth specimen. 2 1/2″ X 2 1/2″.
Valued at $65
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#2 Sphalerite and marcasite specimen from Potosi, MO. 6″ X 7″. Valued at $75

DSC_2240#3 Rock Tumbler. Valued at $60

Chemistry Rocks Webinar

chemistryrocksacs

The American Chemical Society is hosting a live webinar called “Chemistry Rocks! – Exploring the Chemistry of Rocks and Minerals” on Tue, Oct 24, 2017 from 6:00 PM – 7:00 PM CDT. We are surrounded by rocks and minerals everywhere…in the ground we walk on, the places we work and live, and even in the food we eat. How are chemists experimenting with these fundamental materials to help the world and make our lives better? Ask questions live to the experts regarding the amazing work that is being done in rock and mineral science.

To see the webinar, sign up at GoToWebinar and fill out the form. They will send you an email to confirm. Then, on Tuesday at 6PM Central Time, follow the link in the email, make sure you have your computer’s sound turned on, and enjoy!

Chemistry in Mining

During Earth Science WeekTM, we went to a lecture by Dr. Innocent Pumure from UCM called “Sonochemical Extraction of Arsenic and Selenium from Pulverized Rocks Associated with Mountaintop Removal Valley Fill (MTR/VF) Method of Coal Mining”.

You may be wondering, what is Mountaintop Removal Valley Fill Mining? First, the excavation company blows up (or strips) the top part of the mountain to remove vegetation and expose the coal seams. The coal seams are then mined through the open cast/strip method, and the extra rock and soil is dumped in nearby valleys called valley fills. It is cheaper and easier to do than regular mining, where they dig a vertical shaft down and do everything through the tunnel, but it blasts the mountain apart and looks ugly. Since 30% of electricity in the USA comes from coal, valley fill mining is still pretty popular.

In 2002, the EPA found too much selenium downstream of a certain mine in West Virginia (we’re not going to say which one). It was over 5 ng/mL, which was the limit back then.[*] 7 years later, there was still an active mine there and the water still had too much selenium. Even worse, the surrounding sediment had 10.7 mg/kg selenium. This could cause problems for the environment later. Due to bioaccumulation, you could say once it’s in there, it’s really in there.

So now we get to the topic of Dr. Pumure’s talk, in which he and his colleagues discovered a way to quickly find out how much selenium and arsenic were in the ground around this mine in West Virginia. When you do a chemical analysis, you usually have to break down the samples in order to measure what is in them. One method to do this would be to take some core samples and do an acid extraction, but that takes a long time and uses a lot of reagents. Sonochemical extraction uses ultrasound energy to accelerate the leaching process that would naturally happen as rocks become weathered. Since it is ultrasound, it does not directly touch the sample, is minimally invasive, and does not need any reagents except water.

Next, he explained the methodology, which means a description of exactly how they did it in the lab: the size of the extraction cells, how much water and power were used (200W/cm3), how long the samples were sonicated, and all the other pertinent information for chemists. Pumure actually spent quite a lot of time finding out the optimal sonicating time to get the best extraction. It turned out the best times for his sample sizes were 20 minutes for Se and 25 minutes for As. That’s really fast![**] Then, he did a comparison to a chemical sequential extraction to make sure that the sonochemical extraction method was getting everything. To summarize, yes it was. Finally, he did a principal component analysis of core samples from different places all over the mountain using this same technique. They found some really interesting trends and correlations, for example, it appears that there is more arsenic in illite clay than other types of clay.

This research has many useful applications. If you were running a mine, you could take samples more frequently to see if your mine is polluting the surrounding environment, and then you could do something about it before the EPA finds out. The method could probably be used for other analytes, too. For other research needs, you could now quickly analyze large batches of mineral samples to get lots of data that would otherwise be too expensive or time consuming to obtain.

[*]The EPA has since lowered the limit and now it is 3.1 ng/mL.
[**]For comparison, some of my colleagues do chemical extractions that take 2 days.

Extremely Hard Water

A metal pipe completely filled with white gypsum crystals

Steve Hardinger and Dragon Minerals. Retrieved from Mindat Photo of the Day

Everyone knows Kansas City’s water tastes really good, despite being “hard water.” Kansas City municipal water averages 100 ppm (CaCO3 equivalent), which is classified as “moderately hard” by the Water Quality Association. But these people’s hard water would be off the charts!

A valve was stuck in a pipe somewhere in the Naica mining complex in Chihuahua, Mexico. “The valve was removed with the aid of a saw, and voila! the pipe was completely clogged with fine, colorless and gemmy gypsum crystals to 7 cm.”

No word on what they did with the crystals after they unclogged the pipe.

Sources: https://www.mindat.org/photo-773687.html

https://water.usgs.gov/edu/hardness.html