Rock Hound Education

Rock Hound Mineral Science Education Page

The purpose of this page it to provide Minnesota Mineral Club members with various interesting mineral science resources.  These topics could be used in Outreach Events, Club Meetings, Kids Education or just for nerd rock hounds to peruse.

Periodic Table & Minerals

“Dmitry Mendeleev first proposed the Periodic Table of the Elements to the world back in 1869. But fewer people know that he was also a mineral collector. And fortunately his collection is still intact and on display in St. Petersburg University in Russia.” Mindat

Periodic Table Links

Mindat periodic Table: Good starting point.  Click on an element to find out details about this element and related mineralogy.

Webelements.com: Explore key information about the chemical elements with interactive periodic table

Ptable.com: Technical periodic table

Periodictable.com: Stunning visual periodic table with examples of each element

Periodic Table: Mineral Identification Coalition

Periodic Table Song

Mineral Identification

Use the mineral’s properties to determine its identity along with comparison to like mineral found in the same area.  Many web sites will walk you through mineral identification methods – these usually involve systemic property analysis vs. a chart.   Several field books are available for reference while in the field.  Note that the properties are determined by the chemical composition and crystal structure, or the way that the atoms are arranged.  Mindat is great for mineral identification help with its large locality reference material.

Mineral Identification Links

Webelements.com: Explore key information about the chemical elements with interactive periodic table

Ptable.com: Technical periodic table

Periodictable.com: Stunning visual periodic table with examples of each element

Wiki Mineral Identification: Good basic walk through of color, luster, streak, hardness, density, cleavage, fracture, fluorescence, magnetism, radioactivity, smell, etc.

 

Mineral Identification Strategy

Lapidary

A lapidary (lapidarist, Latin: lapidarius) is an artist or artisan who forms stone, minerals, or gemstones into decorative items such as cabochons, engraved gems, including cameos, and faceted designs.[1][2] The primary techniques employed are cutting, grinding, and polishing.[2][3] Carving is an important, but specialised technique.[3]

Hardstone carving is the term used in art history for objects produced by the specialised carving techniques, and the techniques themselves. Diamond cutters are generally not referred to as lapidaries, due to the specialized techniques which are required to work diamond. In modern contexts “gemcutter” typically refers to people who specialize in cutting diamonds, but in older historical contexts it refers to artists producing engraved gems such as jade carvings and the like. By extension the term “lapidary” has sometimes been applied to collectors of and dealer in gems, or to anyone who is knowledgeable in precious stones.[4]Wiki

Lapidary Links

Lapidary

Lapidary Tutorial

Rock Talk with William Cordua

Our club member Prof. Bill Cordua has generated many great Rock Talks that are specific to the geology of our collecting region!

Mineral Identification

Glaciers in Your Backyard

Wisconsin's Ancient Mountains

Reading the Rock in Interstate Park

Meteorites and Wrongs

Ancient Oceans on Top of Our Hills

The Rock Elm Meteorite Crater

Watch for Fallen Rock

Fluorescent Minerals

Fluorescence in minerals occurs when a specimen is illuminated with specific wavelengths of light. Ultraviolet (UV) light, x-rays, and cathode rays are the typical types of light that trigger fluorescence. These types of light have the ability to excite susceptible electrons within the atomic structure of the mineral. These excited electrons temporarily jump up to a higher orbital within the mineral’s atomic structure. When those electrons fall back down to their original orbital, a small amount of energy is released in the form of light. This release of light is known as fluorescence. [Basic Concepts in Fluorescence: Michael W. Davidson and others, Optical Microscopy Primer, Florida State University]

Fluorescent Minerals Links

Geology.com: Nice high level summary of fluorescence in minerals

Light Safety: Safety need to know material when using UV lights

FloridaStateUniversity: Good technical overview

Fluorescent Mineral Society: Main society for fluorescent mineral collectors

 

 

How Fluorescence Works

Dana Mineral Classification

The serious collector will want to classify their collection of minerals.  Several software programs are available which use the Dana Classification system.    The intent of the system is to group minerals together using both chemistry (periodic table) and crystal structure. The numbers that are associated with the Dana system help to group minerals into lists of like minerals.   Similar to some biology classification systems the first division is into classes based on composition or, in the case of silicates, on dominant structural elements.  The first number  represents the class of the mineral. The second number represents the type of mineral which in some cases is based on the atomic characteristics. The third number represents the group to which these minerals belong based on structural similarities. The fourth number is assigned to the individual mineral species.   See the links below for more details or search at Mindat.  The 8 classes of minerals are: Native Elements, Silicates, Oxides, Sulfides, Sulfates, Halides, Carbonates, Phosphates, Mineraloid (Others).

James Dana Father of Mineralogy

Lake Superior Agate Formation

The exact formation methodology of Lake Superior agates is disputed by content experts.  The general geology transition to create Lakers, as described by Wiki below, is agreed upon.   Several book authors disagree on if the silicate rich minerals were slowly deposited into gas voids already in the lava, or if the silicate minerals already within the “glob” preferentially nucleated on the inners surface while coming out of solution during cooling.  The same arguments go for Oregon Thunder Eggs formation, which are similar in nature.   Comments/opinions welcome.

“More than a billion years ago, the North American continent began to split apart along plate boundaries. Magma upwelled into iron-rich lava flows throughout the Midcontinent Rift System, including what is now the Minnesota Iron Range region. These flows are now exposed along the north and south shores of Lake Superior. The tectonic forces that attempted to pull the continent apart, and which left behind the lava flows, also created the Superior trough, a depressed region that became the basin of Lake Superior.

The lava flows formed the conditions for creation of Lake Superior agates. As the lava solidified, water vapor and carbon dioxide trapped within the solidified flows formed a vesicular texture (literally millions of small bubbles). Later, groundwater transported ferric iron, silica, and other dissolved minerals passed through the trapped gas vesicles. These quartz-rich groundwater solutions deposited concentric bands of fine-grained quartz called chalcedony, or embedded agates.

Over the next billion years, erosion exposed a number of the quartz-filled, banded vesicles—agates—were freed by running water and chemical disintegration of the lavas, since these vesicles were now harder than the lava rocks that contained them. The vast majority, however, remained lodged in the lava flows until the next major geologic event that changed them and Minnesota.

During the ensuing ice ages a lobe of glacial ice, the Superior lobe, moved into Minnesota through the agate-filled Superior trough. The glacier picked up surface agates and transported them south. Its crushing action and cycle of freezing and thawing at its base also freed many agates from within the lava flows and transported them, too. The advancing glacier acted like an enormous rock tumbler, abrading, fracturing, and rough-polishing the agates.” [source: Wiki]

Lake Superior Agate

Lake Superior Agate Hunting Tips



		

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