Our friends down in Nebraska are holding their Rock Show this Labor Day weekend! If you’re in the neighborhood, go check them out!
The Annual Pine Cone hunt will be held on Sunday, September 13, 2020 for members only. We will meet at the Park on Hwy 6 going South out of Mandan. Be there before 9 A. M. as we leave at 9:00 A. M. sharp. The park is just South of the Mandan Municipal Golf Course on the west side (right hand side going South) of the road.
Please follow public health guidelines for the Covid-19 public health safety. Wear a mask and follow social distancing.
[Guest Author Matt Doyle]
Hematite, famous modernly for the steel-grey jewelry often made from it, is more commonly a rust-red ore when found in mining iron. A iron oxide (Fe2O3), hematite’s name comes from haema, the Greek word for blood, and most of its direct historical impact comes from that red form. While hematite is incredibly common – the most common form of iron ore – even in ancient times it was appreciated for itself, and not only for the metal it could produce. In modern times, magnets are used to harvest hematite from mine tailings.
Red hematite most commonly possesses an earthy luster, appearing anywhere from rust-colored to Powdered red hematite is also known as rouge. Perhaps most famous as a cosmetic used for centuries to redden the skin, it is the same substance as jeweler’s rouge, used to polish metal and gemstones, and also frequently used to help strop a barber’s straight razor. Red ochre and yellow ochre painting pigments also owe their color to a mixture of red hematite and clay – unhydrated in red ochre, and hydrated in yellow. Maybe most strikingly, hematite is the basis of red chalk, and red chalk drawings have many prominent places in human history and the history of art, including the sketches of Leonardo DaVinci, the body painting of corpses in paleolithic cultures one hundred and sixty to eighty thousand years ago, and numerous cave paintings dating back as much as forty thousand years. Red chalk mines dates back as far as 5000 BCE.
Grey hematite, unlike the “bloodstone” variety that gave it its name, has a metallic luster, and can appear almost like a dark mirror when sufficiently polished. Faceted, it appears nearly black, and smooth, it has a gray, lustrous tone similar to a black pearl. Used as a gemstone in jewelry, for gilding, or for carved intaglios, it was especially popular in Victorian England, and is still used today, in part because it is common enough to be relatively affordable. In its more jewel-like form, it has been sought after for over two millennia, since the Etruscans found deposits of it on the island of Elba.
Outside of iron mines, hematite is commonly found in banded iron formations, hot springs, clay banks, and other places where iron interacts with water (or more rarely, without water, as a result of volcanic activity). Whether grey or red, it always leaves a red streak (and a grey stone leaving a red streak is often striking and startling to students in the lab seeing it for the first time). Hematite often contains enough inclusions of magnetite to appear attracted to magnets, however, hematite itself is only weakly ferromagnetic when encountered at room temperature. Its specific magnetic properties are variable in peculiar ways depending on the scale of the hematite crystal, and its small magnetic moment, as well as the temperatures at which it transitions from antiferromagnetic to paramagnetic, have been the subject of much discussion since the 1950s (and as such, could make up an essay – or many scholarly papers – of their own).
Come join us on July 10th, 1pm, up at Harmon Lake to learn about Cannonball Concretions. Follow 1806 north of Mandan, about 11 miles. Shelter 2.
Large piece of tourmaline for sale, about 8″ tall – taking offers.
Contact Patrick Cool at firstname.lastname@example.org
14″ rock cutting saw, 1 new blade, extra blade cutting oil
Polisher with stand & water drip pail
8 rock tumblers: 3-30lb capacity
Combination trim saw, grinder & shaper, sander & polisher
A lot of extra parts – some new, some used
New price would be over $5000, but I will sell all of this for $2500.
101 Stewart Ave, Box 736
Underwood, ND 58576
Treasures of Sea & Earth supply grit for your rock tumbling needs. For club discounts, please see the Member page. For more information, please check out http://treasuresofseaandearth.com/ Currently available:
400 5lb: $30.00 1lb: $6.00
600 5lb: $30.00 1lb: $6.00
46/70 5lb: $18.80 1lb: $4.00
120/220 5lb: $21.00 1lb: $4.20
Tin Oxide 5lb: $145.00 1lb: $29.00
Tripoli Powder 5lb: $18.80 1lb: $4.00
Plastic pellets 1lb: $4.20
The mild-mannered gypsum is not only a pretty sulfate to look at, but is harvested for numerous functions. The crystals are tabular, and often twinned. It can also form massive, granular, and fibrous habits. Radiating forms are called “daisy gypsum,”, and rose-shaped forms “desert rose.” Gypsum tends to be fairly drab with color, varying from near colorless, white, and gray, to a more green, yellow, or reddish hue. Its name comes from the Greek word “gypsos,”, meaning chalk or plaster.
It is mined for use as a fertilizer, plaster, chalk, and sheetrock / gypsum board. The granular form called alabaster is used in carving and sculpture. “Plaster of Paris” is dehydrated gypsum – by adding water back into the powder, the mixture creates an exothermic reaction (gives off heat), and “sets” into a hardened form. This is useful for making casts of objects. The fibrous crystal form is called “satin spar” and “senelite.”
Gypsum has a white streak, but ranges from transparent to opaque. It is a very common mineral found in many locations. It can be deposited from lakes and seawater, hot springs, and other evaporative environments.
**Becky Trivia** Two fossil sites across North Dakota, on opposite ends of the state, hold gypsum. To the east, the Pembina Gorge locality once held a vast inland sea. Gypsum is so plentiful there it is the main mineral replacing the mosasaur and fish fossils, giving them a very soft, fragile form. Just off site, people can wander and pick up satin spar spears ranging from clear to black. To the west, the Whiskey Creek locality was once a swampy environment similar to the everglades. Sheets of gypsum can be found in and around those crocodile fossils as well.
The chemical formula is CaSO4·2H2O, and a hardness of 2 on the Mohs scale.
Pellant, Chris. Rocks and Minerals. New York: Dorling Kindersley, 1992. Print. Pg. 110.
Hello members! The program following the club meeting on January 10th will be about making gemstone trees. You’ve probably seen them around – eBay, Amazon, etsy – they’re all the rage. Becky will provide take-home printed directions, gemstones (rose quartz, lapis lazuli, amethyst, malachite, and more) and wires enough to build a small tree (like the one above). She has a limited number of needle-nose pliers however, so if you have some lying around, please bring them too! Once you have the basics, no doubt your trees will grow and grow.