Nature and Science Programs at Wonder Works

ESCONI Juniors — Grab Bag Specimens
March 4, 2016, 5:30 am
Filed under: ESCONI, Rock Hunters

One of the free activities at the 2016 ESCONI Juniors booth was the ESCONI Grab Bag. When children arrived at the booth, they were given a brown paper lunch bag. They could select one each of eight different rock, mineral, fossil, and shell specimens to add to their bag. Photos and identification information about the Grab Bag specimens is located further down on this page. First, here are two photos that show what the Grab Bag table looked like in 2014:


The rest of this page consists of close up photos, names, and additional information  about the specimens that were included in ESCONI Grab Bags at the 2015 and 2016 shows. For each type of specimen we give as much information as we have about it. However, because some donors did not provide much information about their specimens (or that information was misplaced during storage), we sometimes don’t know where specimens were found or, for fossils, how old they are.


NOTE:  We will be adding more specimens to this page during the next few days, as we add more specimens to the Grab Bag activity. We will also add more information and links about these specimens as time allows, so be sure to check back here during the week after the ESCONI show.


Specular Hematite, Michigan


Specular Hematite is a type of iron ore made up of tiny, shiny, flattened crystals of hematite. The specimens passed out at Wonder Works came from the iron-mining region of Upper Michigan. Click here to learn more about the mineral hematite.

Selenite Crystals:

Selenite is the crystalline  form of the mineral, gypsum. We are not sure where these crystals were found, although specimens like these can be found in Illinois:


Hourglass Selenite Crystals, Oklahoma

Selenite is a crystal form of the mineral gypsum. These particular selenite crystals are a very special variety from the Salt Plains region of Oklahoma:


The crystals grew inside the salty, sandy soil of this region, trapping sand inside the crystals. Because the sand often forms an hourglass-like shape inside the transparent crystals, this variety is called Hourglass Selenite. Growing crystals sometimes bumped into each other, forming interlocked shapes.  Click here to learn more about Hourglass Selenite.

Amethyst Chips

Amethyst is a purple variety of the mineral quartz:


Quartz Chips:

This chips were broken off of larger crystals of clear or slightly milky quartz:



Chalcedony is a variety of the mineral, quartz, with crystals that are super small — too small to be seen without a powerful microscope. These pieces of chalcedony have been run through a rock tumbler, although only a few of them took a good polish:



The small polished rocks at the Grab Bag table are a mix or mineral, rock, and fossil specimens:



The pieces of broken geode in this photo came from specimens that were found in southwestern Illinois:


The two specimens on the left in this photo show the dull-looking outside of the geodes. The two pieces in the middle show the tiny quartz crystals that line the insides of most of the broken geodes. The geode piece on the lower right shows calcite crystals, which we found in a few geodes. The upper right specimen shows the coating of white clay found in some of our geodes.(This kind of clay is made of crystals so small that they are hard to see even with a microscope.)

Click here to learn more about the geodes found in Illinois.

Click here to learn about one place you can collect geodes in Illinois.



Apache Tears, Western United States

Apache tears are rounded lumps of obsidian, also known as volcanic glass:



Pumice is a type of volcanic rock. It formed from the same type of lava that makes obsidian, but it was very bubbly as it cooled:



The coal in the photo below was broken off of rounded lumps of coal that washed up on a Lake Michigan beach:


The Grab Bag table also gave away small bags containing pieces of Illinois coal (at least while supplies lasted).


Taconite is a processed form of iron ore. It is often transported by train through the Chicago area on its way from the Minnesota iron Ranges to steel mills on southern Lake Michigan, so you can find spilled taconite along local railroad tracks:




Fossil Sea Life from Illinois

The Grab Bag table included specimens of ancient sea animals from several localities. For instance, this sample from Ogelsby, Illinois, dates back to the Pennsylvanian period (about 300 million years ago) It includes mostly brachiopod shells, but two pieces of crinoid stem and two horn corals in the middle of the photo:


The photo below shows more Pennsylvanian age brachiopods, but these are from the Lone Star Quarry in Illinois:


Petrified Wood

The Grab Bag table included specimens of petrified wood from the western United States. If you look closely, you can see the grain of the original wood preserved in rock:


Fossil Shark and Ray Teeth from Africa

These fossil teeth were collected in Morocco. The shark teeth are on the left, and the three ray teeth are on the right:


The sharks and rays lived near the end of dinosaur times, about 60 to 70 million years ago.



The tiny sea shells at the Grab Bag table are a mix of modern day univalves (like snails) and bivalves (like clams). Many of them came from the Indian Ocean:


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