Pyrite is an iron sulfide with two atoms of sulfur for every iron atom, giving it the formula FeS_2. [Ref 1] It is found in varied geological environments, such as in the hydrothermal veins of metal mines, [Ref 1] or in black shales, having as its sources the iron and sulfur from former sea life e.g. [Ref 2]

Because of its brilliant golden color, and often pristine crystal forms, it is a favorite among collectors. Specimens of pyrite from metal mines are often quite spectacular, as seen in the photos below, of Pyrite accompanying the zinc ore mineral Sphalerite and quartz, and alone in crystal clusters as found in metal mines.

Pyrite crystallizes in the cubic crystallographic system. (Ref 1) It exhibits a number of forms, as seen in Figures 1, 2, 3 & 4, either singularly such as the cube, or in combinations of these forms. Scrolling through the gallery of images available when Googling “Pyrite” will show you specimens exhibiting such forms from many worldwide locations.

Pyrite specimens found in black shales rich in organic-materials, occur in a number of interesting forms, found when replacing an animal and forming a fossil or in sun shapes formed of tiny radiating crystals, and as aggregates of small crystals as seen in the photos below.

Above, I’ve emphasized pyrite accompanying other ore minerals. However, pyrite itself used to be an important ore for the production of sulfuric acid and sulfur. (Ref 3) The first step in these recoveries was roasting the ground pyrite in the presence of air. (Ref 4) The past and present most important use of pyrite is as an ore of gold. (Ref 3) In these ores, gold occurs as an impurity. (Ref 5)

Ending on a different note, one type of kidney stone is chemically a calcium phosphate which has the same composition as the mineral Apatite, (Ref 6), an example of one of the minerals present in life forms.

Ref 1 https://www.mindat.org/min-3314.html

Ref 2 http://www.indiana.edu/~sepm04/PDF/JS-J28-pyrite_balls.pdf

Ref 3 http://geology.com/minerals/pyrite.shtml

Ref 4 http://www.saimm.co.za/Conferences/Sulphur2009/101-110_Runkel.pdf

Ref 5 Abstract in: http://www.otago.ac.nz/geology/research/gold/geology-and-gold/gold-and-arsenic.html

Ref 6 https://www.mindat.org/min-29229.html

In sharing ideas about these subjects I will, because of space limitations, provide short but meaty encapsulations. I will draw abundantly from resources on the web. To complement my input, I will usually provide links to the subject for your further exploration. In a lighter vein, I plan to frequently include the rich lore of mining and of mining men, of prospectors, and of Lost Gold and Silver Mines and of the historic mines, particularly in the Southwest and Mexico.

To begin, what is a mineral? Drawing from the site, Webmineral, I find a number of definitions cited from scientific literature.  To synthesize: “a mineral is a naturally occurring homogeneous solid with regularly ordered crystalline structure and a definite chemical composition. They can be distinguished from one another because of these definite characteristics”. Knowledge of these ideas are powerful tools in identifying a mineral specimen. The mineral’s chemical composition leads directly to its color, internal atomic arrangement, and crystal form. For example, the beautiful Rhocochrosite crystal from the Sweet Home Mine in Colorado, shown above, is manganese carbonate, having the chemical formula MnCaCO₃. Its deep red color is due to its manganese content and its rhombohedral form comes from the internal arrangement of atoms.

Because of the importance of chemical and crystallographic relationships in defining a mineral, I’m providing a link to an introductory course to minerology and crystallography offered by the Open University, a long known and excellent United Kingdom source of quality courses offered, at no cost, to world-wide users. I encourage you to open the link and scan the topics offered, as well as the internal links to tools for accessing a comprehensive body of reference material.

I hope you will share your questions and comments with me, submitting them to our “Ask An Expert” feature.

In my next post, I’ll share with you ideas offered by the most senior of collectors on how to build your own collection. Those ideas will include: collecting one mineral species; collecting many; collecting from one locality; collecting worldwide; where to find bargains and much more.

Until then, have fun learning about minerals and collecting.

We followed several dirt tracks just to see where they went and found plenty of the rocks we were looking for – including a few specimens of Petrified Wood sporting delightful druzy crystals.  The Jasper was plentiful in a couple of spots just off the main road into the BLM area we were collecting in.

As several of us hadn’t followed the main road all the way out to the Little Colorado river before, we took that drive, which is well worth it if you enjoy amazing sandstone sculptures.

Today my main topic is the mineral Wulfenite which has a strong association with Arizona. Lead mines, in which Wulfenite has been found, are numerous, with some of them offering such beautiful examples of the mineral that they have become classic localities. Among these are the Rowley Mine and the Glove Mine.   More photos of Wulfenite

Wulfenite, having lead in its composition, is found primarily in lead mines and is widely distributed among Arizona mines as shown on the map of occurences: Map

There are 137 of these mines, with distribution from North to South and East to West. An article by the former Curator of the Arizona Mining and Mineral Museum, Jan C. Rasmussen, identifies eight mines noted for the aesthetics of the Wulfenite specimens found in them, and describes the physical and historical geology of the region, as well as the geochemistry describing the mineral deposition. The author also includes photos of specimens from each mine in this downloadable pdf document.  Arizona Wulfenite by Jan C. Rasmussen

The wide range of yellow to red colors is notable among Arizona specimens. However, for completeness sake, Wulfenite specimens come not only in shades of red, orange, and yellow – as this one in figure #2, from the Glove Mine – but they can also be made black by manganese inclusions, such as the one in figure #3. Other grey to black inclusions of such ore minerals as metal sulfides would have a similar effect.

The beautiful yellow to red colors of Wulfenite deserve mention of their origin. I will paraphrase the explanation in this post by Fred Haynes

Since lead molybdate is colorless or white:  the color must arise from another metal with the same valence as lead. Trace amounts of vanadium, manganese, chromium, and titanium are the source the colors. These elements do this by absorbing the violet, blue, and green parts of the visible spectrum.  Some of the crystal forms evidenced by Wulfenite range between tabular, through blocky, to highly elongated as shown by examples in the Atlas of Crystallographic Forms of Wulfenite and the vast gallery of photographs at its Mindat site, which I linked to at the beginning of this blog. Just click on the icons in the atlas to view these forms. Some of the basic forms evidenced are modified by beveled edges and corners which add to their interest.

On Building a Collection:  In my first blog I stated that I would provide some insights on how to build a collection that would maximize your enjoyment. Rather than paraphrase their content I’ve provided links, below, to the websites which offer sound advice on subjects ranging from the aesthetics of a specimen through pragmatic How To’s, to how to build a collection on a budget. I hope these ideas serve you well in the process of building your collection

Desirable to mandatory specimen attributes: http://farlang.com/how-to-build-a-mineral-collection

Pragmatic advice: http://www.johnbetts-fineminerals.com/jhbnyc/articles/advice.htm

Pragmatic advice including building upon locality, one species, etc:

http://www.mcdougallminerals.com/blog/seven-keys-to-building-a-great-mineral-collection/

AND http://www.minerals.net/resource/Organizing_Mineral_Collection.aspx

Building a collection on a budget: http://www.treasuremountainmining.com/index.php?route=pavblog/blog&id=133

A short personal note:  Shortly after I began collecting, I learned of a mineral dealer named Jack Filer who, with son Russell, dealt in mineral specimens and were located close to my home. Frequently, on a Saturday, with or without money in my pocket, I would go over to visit Jack. Even without purchasing anything, I was welcome to visit, ask questions, eagerly sop up information and hear their stories of mining and collecting, and so wonderfully allowed to hold and pore over specimens, as well as help Jack in curating his collection. All of this was an incredible privilege. I include these remarks not only to reminisce, but to also point out the importance and joys of having a mentor who knows a lot about minerals, communicates well, particularly in question-answer form, and who really cares about you and your education about minerals. Jack and Russell started me out in becoming the collector I remain today. I will always be grateful for them.

Pyrite is an iron sulfide with two atoms of sulfur for every iron atom, giving it the formula FeS_2. [Ref 1] It is found in varied geological environments, such as in the hydrothermal veins of metal mines, [Ref 1] or in black shales, having as its sources the iron and sulfur from former sea life e.g. [Ref 2]

Because of its brilliant golden color, and often pristine crystal forms, it is a favorite among collectors. Specimens of pyrite from metal mines are often quite spectacular, as seen in the photos below, of Pyrite accompanying the zinc ore mineral Sphalerite and quartz, and alone in crystal clusters as found in metal mines.

Pyrite crystallizes in the cubic crystallographic system. (Ref 1) It exhibits a number of forms, as seen in Figures 1, 2, 3 & 4, either singularly such as the cube, or in combinations of these forms. Scrolling through the gallery of images available when Googling “Pyrite” will show you specimens exhibiting such forms from many worldwide locations.

Pyrite specimens found in black shales rich in organic-materials, occur in a number of interesting forms, found when replacing an animal and forming a fossil or in sun shapes formed of tiny radiating crystals, and as aggregates of small crystals as seen in the photos below.

Above, I’ve emphasized pyrite accompanying other ore minerals. However, pyrite itself used to be an important ore for the production of sulfuric acid and sulfur. (Ref 3) The first step in these recoveries was roasting the ground pyrite in the presence of air. (Ref 4) The past and present most important use of pyrite is as an ore of gold. (Ref 3) In these ores, gold occurs as an impurity. (Ref 5)

Ending on a different note, one type of kidney stone is chemically a calcium phosphate which has the same composition as the mineral Apatite, (Ref 6), an example of one of the minerals present in life forms.

Ref 1 https://www.mindat.org/min-3314.html

Ref 2 http://www.indiana.edu/~sepm04/PDF/JS-J28-pyrite_balls.pdf

Ref 3 http://geology.com/minerals/pyrite.shtml

Ref 4 http://www.saimm.co.za/Conferences/Sulphur2009/101-110_Runkel.pdf

Ref 5 Abstract in: http://www.otago.ac.nz/geology/research/gold/geology-and-gold/gold-and-arsenic.html

Ref 6 https://www.mindat.org/min-29229.html

Today my main topic is the mineral Wulfenite which has a strong association with Arizona. Lead mines, in which Wulfenite has been found, are numerous, with some of them offering such beautiful examples of the mineral that they have become classic localities. Among these are the Rowley Mine and the Glove Mine.   More photos of Wulfenite

Wulfenite, having lead in its composition, is found primarily in lead mines and is widely distributed among Arizona mines as shown on the map of occurences: Map

There are 137 of these mines, with distribution from North to South and East to West. An article by the former Curator of the Arizona Mining and Mineral Museum, Jan C. Rasmussen, identifies eight mines noted for the aesthetics of the Wulfenite specimens found in them, and describes the physical and historical geology of the region, as well as the geochemistry describing the mineral deposition. The author also includes photos of specimens from each mine in this downloadable pdf document.  Arizona Wulfenite by Jan C. Rasmussen

The wide range of yellow to red colors is notable among Arizona specimens. However, for completeness sake, Wulfenite specimens come not only in shades of red, orange, and yellow – as this one in figure #2, from the Glove Mine – but they can also be made black by manganese inclusions, such as the one in figure #3. Other grey to black inclusions of such ore minerals as metal sulfides would have a similar effect.

The beautiful yellow to red colors of Wulfenite deserve mention of their origin. I will paraphrase the explanation in this post by Fred Haynes

Since lead molybdate is colorless or white:  the color must arise from another metal with the same valence as lead. Trace amounts of vanadium, manganese, chromium, and titanium are the source the colors. These elements do this by absorbing the violet, blue, and green parts of the visible spectrum.  Some of the crystal forms evidenced by Wulfenite range between tabular, through blocky, to highly elongated as shown by examples in the Atlas of Crystallographic Forms of Wulfenite and the vast gallery of photographs at its Mindat site, which I linked to at the beginning of this blog. Just click on the icons in the atlas to view these forms. Some of the basic forms evidenced are modified by beveled edges and corners which add to their interest.

On Building a Collection:  In my first blog I stated that I would provide some insights on how to build a collection that would maximize your enjoyment. Rather than paraphrase their content I’ve provided links, below, to the websites which offer sound advice on subjects ranging from the aesthetics of a specimen through pragmatic How To’s, to how to build a collection on a budget. I hope these ideas serve you well in the process of building your collection

Desirable to mandatory specimen attributes: http://farlang.com/how-to-build-a-mineral-collection

Pragmatic advice: http://www.johnbetts-fineminerals.com/jhbnyc/articles/advice.htm

Pragmatic advice including building upon locality, one species, etc:

http://www.mcdougallminerals.com/blog/seven-keys-to-building-a-great-mineral-collection/

AND http://www.minerals.net/resource/Organizing_Mineral_Collection.aspx

Building a collection on a budget: http://www.treasuremountainmining.com/index.php?route=pavblog/blog&id=133

A short personal note:  Shortly after I began collecting, I learned of a mineral dealer named Jack Filer who, with son Russell, dealt in mineral specimens and were located close to my home. Frequently, on a Saturday, with or without money in my pocket, I would go over to visit Jack. Even without purchasing anything, I was welcome to visit, ask questions, eagerly sop up information and hear their stories of mining and collecting, and so wonderfully allowed to hold and pore over specimens, as well as help Jack in curating his collection. All of this was an incredible privilege. I include these remarks not only to reminisce, but to also point out the importance and joys of having a mentor who knows a lot about minerals, communicates well, particularly in question-answer form, and who really cares about you and your education about minerals. Jack and Russell started me out in becoming the collector I remain today. I will always be grateful for them.

In sharing ideas about these subjects I will, because of space limitations, provide short but meaty encapsulations. I will draw abundantly from resources on the web. To complement my input, I will usually provide links to the subject for your further exploration. In a lighter vein, I plan to frequently include the rich lore of mining and of mining men, of prospectors, and of Lost Gold and Silver Mines and of the historic mines, particularly in the Southwest and Mexico.

To begin, what is a mineral? Drawing from the site, Webmineral, I find a number of definitions cited from scientific literature.  To synthesize: “a mineral is a naturally occurring homogeneous solid with regularly ordered crystalline structure and a definite chemical composition. They can be distinguished from one another because of these definite characteristics”. Knowledge of these ideas are powerful tools in identifying a mineral specimen. The mineral’s chemical composition leads directly to its color, internal atomic arrangement, and crystal form. For example, the beautiful Rhocochrosite crystal from the Sweet Home Mine in Colorado, shown above, is manganese carbonate, having the chemical formula MnCaCO₃. Its deep red color is due to its manganese content and its rhombohedral form comes from the internal arrangement of atoms.

Because of the importance of chemical and crystallographic relationships in defining a mineral, I’m providing a link to an introductory course to minerology and crystallography offered by the Open University, a long known and excellent United Kingdom source of quality courses offered, at no cost, to world-wide users. I encourage you to open the link and scan the topics offered, as well as the internal links to tools for accessing a comprehensive body of reference material.

I hope you will share your questions and comments with me, submitting them to our “Ask An Expert” feature.

In my next post, I’ll share with you ideas offered by the most senior of collectors on how to build your own collection. Those ideas will include: collecting one mineral species; collecting many; collecting from one locality; collecting worldwide; where to find bargains and much more.

Until then, have fun learning about minerals and collecting.

We followed several dirt tracks just to see where they went and found plenty of the rocks we were looking for – including a few specimens of Petrified Wood sporting delightful druzy crystals.  The Jasper was plentiful in a couple of spots just off the main road into the BLM area we were collecting in.

As several of us hadn’t followed the main road all the way out to the Little Colorado river before, we took that drive, which is well worth it if you enjoy amazing sandstone sculptures.