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                           Mineral of the Month--January

                  Strontianite

                                       Strontium Carbonate

                              SrCO3

                   Strontianite Basics & Geology

               By Karissa Hendershot and  Ken Casey

Preface
Introduction
Basics & Geology

Article Contributors
Photo & Graphics Credits
Suggested Reading
Invitation to Members
Past Minerals of the Month
Strontianite600.jpg (312618 bytes)
 

With crystals like snowballs...

 

...Strontianite can remind us of  a cold winter!

The above image is courtesy of Stan Celestian, Glendale Community College 2005

Preface    

     This month's article features a local favorite to our club: Strontianite.  Our President, Karissa
Hendershot and I have collaborated to bring you a new mix of facts and a geological story.   Are
you ready for our brief visit with Strontianite?  Let's go!

Introduction

     Today, we embark on a study session, as fieldtrip season is at a close for our club's area. 
Let's "bone up" on our strontium minerals a bit, so that we may be prepared in March-April of
2006 to collect again.  Please join us at the table.  Here, I'll pass you each a study guide to
get started.  You begin, while I rustle us up some refreshments.

2813tn.jpg (30713 bytes) 2813a.jpg (27744 bytes)
Light green Aragonite pseudo-hexagonal crystals on a creamy matrix of Strontianite crystals, Argriento, Sicily, Italy
Images courtesy of Isaias Casanova of IC Minerals 2005-6

 

Basics & Geology

 

Strontianite

Strontianite Basics
by Karissa Hendershot

     Strontianite is named after its discovery locality in Strontian, Argkyllshire, Scotland.

PHYSICAL CHARACTERISTICS:

1.                Chemical Name and Formula: Strontium Carbonate, SrCO3

2.                Class: Carbonate

3.                Color: Generally colorless to white but is also found in pink, grey and green.

4.                Luster: Vitreous to greasy

5.                Transparency: Transparent to Translucent with a glassy luster

6.                Crystal System: Orthorhombic

7.                Crystal Habits include compact, granular, concretionary and massive forms. Crystals are uncommon and are usually pointed and nearly acicular in radiating clusters or tufts. Also forms a pseudo-hexagonal trilling twin is similar to, but is far rarer than aragonite's famous twin.

8.                Cleavage is notable in one direction and poor in another,

9.                Fracture is subconchoidal to uneven

10.            Hardness: 3.5 – 4 (Copper Penny)

11.            Specific Gravity: 3.7+, (above average for transparent minerals)

12.            Streak: White

13.            Solvency: effervesces in only warm HCl solutions or when powdered in cold HCl.

14.            Associated Minerals include: Magnesite, Calcite, Celestite

15.            Ultraviolet: fluoresces bright blue-white under UV illumination

16.            Best Field Indicators are crystal habits, reaction to acid and density

 

     Notable Occurrences include: Strontian, Scotland; San Bernito Co, California and Cave-in-rock, Illinois, USA; Austria and Germany and of course Meckley Quarry in Bedford, Pennsylvania

 

     The element Strontium is found predominately in two minerals, strontium sulfate (SrCO4), known as Celestite and strontium carbonate (SrCO3), know as Strontianite. 

 

strontianite_JPG.jpg (36989 bytes) ShowFullPic2.jpg (146584 bytes)
Strontianite Crystals Close-up of Strontianite Crystals

Greene Gallery Mineral Collection,
University of Milwaukee
Department of Geosciences 2005-6

The Perkins Geology Museum,
University of Vermont
2005-6

 

     Strontianite is found in low-temperature hydrothermal veins associated with calcite, celestite and sulfides such as found at Meckley Quarry in Bedford, Pennsylvania.

     It was mined for a while in Germany for strontium, an element used as a coloring agent of fireworks and other applications.

     Strontium is a metallic element that commonly occurs in nature; only two minerals, Celestite (strontium sulfate) and Strontianite (strontium carbonate), however, contain Strontium in sufficient quantities to make its recovery practical. Crystals are rarer than the massive forms, and so are usually sold as specimens. Typical specimens have spiky, minute crystals in radiating aggregates or tufts. However, it also forms pseudohexagonal twins similar to aragonite's famous twin. Of the two, Celestite occurs much more frequently in sedimentary deposits of sufficient size to make mining attractive.

 

COMMERCIAL USES FOR STRONTIANITE:

     Strontium ores for commercial use have not been mined in the United States since 1959. The world's largest producers are, in descending order of output, Mexico, Spain, and China. The United States imports its commercial Celestite from Mexico. It is processed into a variety of strontium chemicals that are used mainly in the faceplate glass of color television picture tubes. Strontianite is also used in fireworks to create the deep red colors, and in the sugar beat industry.

References:

  1. Simon & Schuster’s Guide to Rocks and Minerals
  2. www.Mindat.org
  3. http://www.theimage.com/mineral/strontianite/index.htm
  4. http://mineralgalleries.com
  5. Strontium by Joyce A. Ober
  6. www.Speclab.com
  7. http://resourcescommittee.house.gov/subcommittees/emr/usgsweb/materials

 

Strontianite Geology
by Ken Casey

     Though a rare mineral, Strontianite can capture our imagination, if we choose to delve into its ice-like crystal forms.  Like a miniature snowscape, our MOTM resembles ice, but does not crystallize in its forms.  Supported by its vuggy matrix, white ball-like clusters cap the edges of open spaces to create a mock arsenal of snowballs for a fictional small scale snowball fight amongst children on a bright winter’s day in extreme northern or southern climes.  A model railroader might consider using his or her specimens to crown a train layout.

     As a thumbnail or larger mineral specimen in your collection, you can appreciate your Strontianite in at least two other ways: in daylight, or under fluorescent light.

     In daylight, it can almost glow a bright white in its druzy or snowball-shaped forms.  Its nearly transparent, acicular crystals can also impart this glow.

     Strontianite fluoresces a weak white both under Longwave (LW) and Shortwave (SW) ultraviolet light.  Sometimes a pale blue or blue-green color can be exhibited.

     Winfield Quarry in Pennsylvania (now closed to collecting) has been a good source of twinned golden calcite crystals and spherical, white Strontianite clusters.  Meckley’s Quarry in Mandata, PA also offers similar strontium carbonate crystals, but with clear blue Celestite (strontium sulfate).  These rare fibrous crystals can appear to resemble snow and tiny snowballs.  The matrix is vuggy limestone in both of these southeastern Pennsylvania locales.  This author has a few specimens from one of Meckley’s generous open houses.  But, like some of us in the hobby, have so much in our collections over the years, cannot find one to photograph for this article.  I will, however offer to links of some folks who have had greater success therein.

     Many such limestone beds around the world are chemically suited to be used as a raw material in either concrete blocks or hydraulic cement.  Typically, such minerals as calcite, aragonite, Strontianite, celestite, and epsomite, pyrite, and fluorite accompany Strontianite in similar assemblages forming in limestone cavities.  Our club’s fieldtrip area encompasses many of these sites.  Quartz in magnesium dolomites is also a possibility.  Hydrothermal veins, however, can deposit more metallic ore minerals, like galena and sphalerite.  Even gypsum (a sulfate) and chalk (a limestone) have been associated with Strontianite in certain North American and European geologic environments.

     Much of the world’s karst topographies could yield strontium-based minerals.  Ancient sedimentary seabeds metamorphosed over time into dolostone.  In his book, Oxygen : The Molecule that Made the World , Nick Lane relates many of the earth’s geologic processes and depositions to organic processes.  One theory of formation suggests deep marine deposition of strontium derived in part from earlier life. 

     Some studies have been done comparing the Sr87:Sr86 isotopes.  By comparing the ratios of these radiogenic sediments, we can ascertain a proposed age of the earth, or even radiometrically date geologic strata, hence key into the geologic paleoenvironments that formed them. 

     They may also be used as key isotopic indicators in petrology, specifically in diamond-mining.  So, strontium is important in geologic research.  Perhaps there are some hidden new theories we could derive from a further study of concentrated Strontianite deposits.

     As a note of caution to our proposed studies, you might want to be mindful that pure metallic strontium can be toxic to humans, as it prefers to replace calcium in teeth and bones.  In fact, bone marrow cancer is one likely scenario.  Professional scientists are trained to handle it in its elemental form.  As we are concerned only with more stable minerals forms, we are working a greatly safer compound.  Of course, these minerals, though resembling edible salts, are not to be consumed, unlike halite salts.  So, please, do not use the “taste test” to aid in identifying this salient mineral.  Your safety is of paramount importance to us.

     As our planet supports life, especially that of mineral enthusiasts like yourself, you may wish to study up on Strontianite, and how it can help you to better understand our universe.  Perhaps you may desire to travel to a famous collecting site, or even visit a local rock & mineral show to swap or purchase specimens for yourself, or to share with others. 

     We hope that you have enjoyed our brief coverage on the identification and geology of our favored strontium mineral this month.

Until Next Time

    
     Until then, stay safe, and happy collecting. hardhat2a.gif (5709 bytes)

 

Links

 

Article Contributors


Isaias Casanova, IC Minerals

Stan Celestian, Glendale Community College, Glendale, Arizona

Susan Celestian, Curator, Arizona Mining and Mineral Museum

Jolyon Ralph, Mindat.org

University of Milwaukee, Department of Geosciences, Greene Mineral Collection

The Perkins Geology Museum, University of Vermont

 

Photo & Graphics Credits

I would like to gratefully acknowledge the generous contributions of our fellow Strontianite
enthusiasts, collectors, authors, curators, professionals, and club members who made this
work possible. 
Thanks.


Isaias Casanova, IC Minerals

Stan Celestian, Glendale Community College, Glendale, Arizona

Susan Celestian, Curator, Arizona Mining and Mineral Museum

Jolyon Ralph, Mindat.org

University of Milwaukee, Department of Geosciences, Greene Mineral Collection

The Perkins Geology Museum, University of Vermont



2005  All contributions to this article are covered under the copyright protection of this article
and by separate and several copyright protection(s), and are to be used for the sole purposes of
enjoying this scholarly article.  They are used gratefully with express written permission of the
authors, save for generally-accepted scholarly quotes, short in nature, deemed legal to reference
with the appropriate citation and credit.  Reproduction of this article must be obtained by express
written permission of the author, Kenneth B. Casey, for his contributions, authoring, photos, and
graphics.  Use of all other credited materials requires permission of each contributor separately
.

Links and general contact information are included in the credits above, and throughout this article.
The advice offered herein are only suggestions; it is the reader's charge to use the information
contained herein responsibly.  DMS is not responsible for misuse or accidents caused from this
article. All opinions, theories, proofs, and views expressed within this article, and in others on this
website, do not necessarily reflect the views of the Delaware Mineralogical Society.
 


Suggested Reading

Strontium by Joyce A. Ober

The Young Potassic Rocks edited by Gupta K. Alok and Fyfe S. William

Oxygen : The Molecule that Made the World by Nick Lane

Celestite and strontianite, (Arizona. Bureau of mines. Bulletin) by Frank Lewis Culin

Strontianite deposits near Barstow, California, (Contributions to economic geology) by Adolph Knopf

The occurrence of strontianite at Sierra Mojada, Mexico by Philip Krieger

Gypsum and anhydrite & Celestine and strontianite, (Geological Survey of Great Britain. Special reports on the mineral resources of Great Britain) by R. L Sherlock

 

 

About the Authors:

 

karissa.jpg (2366 bytes)      Karissa is the current President of the Delaware Mineralogical Society.
E-mail: kdhendershot@delminsociety.net

KEN.JPG (31503 bytes)

     Ken is current webmaster of the Delaware Mineralogical Society.  He has a diploma in Jewelry Repair, Fabrication & Stonesetting from the Bowman Technical School, Lancaster, PA, and worked as jeweler.  He has also studied geology at the University of Delaware.  And, he is currently a member of the Delaware Mineralogical Society and the Franklin-Ogdensburg Mineralogical Society.  E-mail: kencasey98@yahoo.com.


Invitation to Members

Members,

Want to see your name in print?  Want to co-author, contribute, or author a whole Mineral of the Month article?  Well, this the forum for you!

And Members, if you have pictures, or a story you would like to share, please feel free to offer.  We'd like to post them for our mutual enjoyment.   Of course, you get full photo and author credit, and a chance to reach other collectors, hobbyists, and scientists.  We only ask that you check your facts, give credit where it is due, keep it wholesome for our Junior Members watching, and keep on topic regarding rockhounding.

You don't even have to be experienced in making a webpage.  We can work together to publish your story.  A handwritten short story with a Polaroid will do.  If you do fancier, a text document with a digital photo will suit, as well.   Sharing is the groundwork from which we can get your story out there.

Our club's webpages can reach any person surfing the net in the world, and even on the International Space Station, if they have a mind to view our website!

We are hoping for a possible tie-in to other informative programs upon which our fellow members might want to collaborate.  Contact any officer or board member with your suggestions.

Our next MOTM will be a surprise.  For 2005-6, we are waiting for your suggestions.  What mineral do you want to know more about?

aniagate.gif (1920 bytes)

____________________________________

Most of the Mineral of the Month selections have come from most recent club fieldtrips and March Show Themes, and from inspriring world locales. thus far.  If you have a suggestion for a future Mineral of the Month, please e-mail me at: kencasey98@yahoo.com, or tell me at our next meeting.

 

 

 

       

  


Next Meeting
 

April Program, Monday, April 8, 2013:

"Destruction of the Fossil Exposures in the Chesapeake Bay Area" presented by Dr. Lauck Ward

General Club Meeting:
April 8, 2013
(Monday)

We are meeting at
Greenbank Mill


Special Meetings:
 

*Show Committee Meeting, April or May, 2013

*New Home/Lapidary Committee, 2013

*Board Meeting,  April, 2013

Next Field Trips
 

Fieldtrips!

Past Fieldtrips
 

Next Show
DMS March Show
March 1-2, 2014 at DelTech Stanton

 


Our 2013 Show Theme was:
"All That Glitters is as Good as Gold!"

March Show 2013 Report

Updates!

 

 

 
Articles

 

Fossil Forum


"Dinny, the Dino"

"Belemnites are coming"

 

MOTM June also commemorates our 50th Show!

It's shiny, yellow, and is a symbol of 50 Years!Can you guess?

Past MOTM

Collecting Adventure Stories:

"Sunny Brook Crick Goethite" by Joe Dunleavy