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                           Mineral of the Month--December


                                              Calcium Iron Silicate



                                              By Karissa Hendershot

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Article Contributors
Photo & Graphics Credits
Suggested Reading
Invitation to Members
Past Minerals of the Month
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Colors of red & green...


...represent part of the holiday season!
(Top, left): Hedenbergite, Byram Quarry, New Jersey
Photo courtesy of Karissa Hendershot ©2006

(Top, right): Green Hedenbergite, Russia
Photo by and courtesy of IC Minerals  ©2006


     This month, we are endeavoring to learn more about: Hedenbergite.

     A classic pyroxene, Hedenbergite even occurs in our club's collecting region in Franklin,
New Jersey.

     Our exploration is more on the lab characteristics and some world locales.  Let's go!



     Welcome to another Mineral-of-the-Month installment! 

     Our focus this month is on: Hedenbergite.  This silicate is a pyroxene, and occurs in
various colors, from green to red to black.  It sometimes occurs with orange garnets or
with pink calcites, giving us specimens with the red/green color combination we mentioned

     Our author this month is Karissa Hendershot, a professional geographer, avid fossil
and mineral collector, and accomplished lapidary.  Enjoy!



By Karissa Hendershot




     The mineral was named after the Swedish chemist, M.A. Ludwig Hedenberg, who first
described the species.


Chemistry: CaFeSi2O6, Calcium Iron Silicate
Class: Silicates
Subclass: Inosilicates
Group: Pyroxenes

Uses: only as a mineral specimen.


     Hedenbergite is a rock forming mineral in several metamorphic rocks, especially contact
metamorphic rocks and skarns. It is also found in some igneous rocks and ore bodies. The
mineral is a part of an important solid solution series of the pyroxene group. The series
includes the minerals diopside, CaMgSi2 O6, and augite, (Ca, Na)(Fe, Mg, Al)(Al, Si)2 O6.
Hedenbergite is the iron rich end member of the series. The diopside-hedenbergite series is
analogous to the amphiobole, tremolite- actinolite series.



Color is black, greenish black, dark green and dark brown.

Luster is vitreous to dull.

Transparency crystals are translucent to opaque.

Crystal System is monoclinic; 2/m

Crystal Habits include short prismatic (with a square cross section) and accicular, rarely
fibrous crystals. Good crystals are rare, more commonly compact, granular, lamellar and

Cleavage is perfect in two lengthwise directions at close to right angles and a basal parting
direction is sometimes seen.

Fracture is uneven to conchoidal.

Hardness is 5 - 6

Specific Gravity is approximately 3.2 - 3.6 (above average)

Streak is white to pale green.

Associated Minerals are wollastonite, grossular, andradite, magnetite, actinolite, galena,
rhodonite and calcite.

Occurrence: common constituent of metamorphosed iron formations or other ferruginous
siliceous sediments; common in Fe-Mn skarns. In alkalic granites, syenites, and in xenoliths
in kimberlite.

Fluorescence:Translucent to transparent; light-colored varieties in dolomitic marble may
fluoresce blue or yellow.

Best Field Indicators are crystal habit, associations, color, fracture and cleavage.

pyroxcomp.gif (10921 bytes)

Phase Diagram containing Hedenbergite in series
Courtesy of Stephen A. Nelson, Tulane University



     Hedenbergite is a member of the clinopyroxenes, which crystallize in the monoclinic
system and contain calcium, iron, aluminum, sodium, or lithium. The crystals commonly
occur as radiating fibrous aggregates, with stubby, prismatic crystals of nearly square cross
section being rarer. They are almost opaque except when slivers viewed on the edge. Fibrous
forms are often greenish-brown in color

     Although usually darker than its gemstone cousin diopside, can still be a wonderful mineral
specimen. Its dark green to black color can be striking with the bright luster that is found on
some specimens. While this is not an uncommon mineral, good crystals of hedenbergite are
rare and specimens that show nice crystals, good color and luster are prized.


Occurrence and paragenesis

     Found in association with minerals of contact metamorphism and of regional metamorphism
of dolomitic limestones. Less frequently in rarer types of pegmatites

     The predominant and most abundant Hedenbergite occurrence is at Franklin, where it occurs
as dark green intergrowths with epidote and at Sterling Hill, where it occurs in several assemblages.

     Being Diopside's Fe-analog, Hedenbergite found in northern New Jersey is greatly magnesian
in content, more closely resembling Diopside.





     A few localities for studied material include: in Sweden, at Nordmark, VÄarmland, and
YxsjÄo, ÄOrebro. From PrÄagraten, Tirol, Austria. At FÄurstenberg, Saxony, Germany.
From RioMarina, Elba, Italy. On Seriphos, Greece. In the USA, at Iron Hill, Gunnison Co.,
Colorado; ¯ne crystals from the Laxey mine, South Mountain, Owyhee Co., Idaho; in the Pima
district, Pima Co., and the Westinghouse mine, Santa Cruz Co., Arizona; at Hanover, Grant
Co., New Mexico.  In the Vesturhorn intrusion, southeast Iceland. Large crystals from Broken
Hill, New South Wales,Australia. In the Obira mine, Bungo, Oita Prefecture, Japan. At Tirodi,
Madhya Pradesh, and Kacharwali, Nagpur district, Maharashtra, India. Fine crystals from the
Skardu area, Pakistan.  At Dal'negorsk, Primorskiy Kray, Russia.


     The pictures show the different habits that Hedenbergite can take.


Ebay Dealer: affordableminerals


Ebay Dealer: socalnevadainc


Ebay Dealer: d-h-garske


Collected at Tilcon’s Byram Quarry in Stanhope, New Jersey in September 2006.
Broken 1+ inch crystals surrounded by pink calcite and tiny books of Muscovite.
The Calcite can be etched out to reveal complete crystals of the Hedenbergite.




3246B.JPG (51691 bytes) Hedenbergite222.jpg (85614 bytes)
Green Hedenbergite,
(Ex. Loud Collection)
aevskiy Deposit, Dalnegorsk, Primorskiy Krai, Russia
Photo by and Courtesy of Isaias Casanova
Prismatic Columns of Hedenbergite w/ Ilvaite crystal,
Owyhee County, Idaho
Photo by and Courtesy of Stan Celestian


HEDESW.JPG (27933 bytes) hedenbergite_alang.jpg (191618 bytes)
Black Hedenbergite,
Nordmark, Sweden
(Smithsonian Collection)
Photo by and Courtesy of C. R. Nave ©2006
Photo by and Courtesy of Alan Guisewite




Hedenbergite, University of Delaware

Hedenbergite at

Dr. Bill's Wisconsin Mineral List: Hedenbergite

Alan Guisewite's Hedenbergite Page

Mineral Description: Hedenbergite


Members' Gallery

Here is where DMS Members can add their Hedenbergite photos to share with us.


Until Next Time

     We hope you have enjoyed our all too short visit to Hedenbergite.  Please join us next month,
for another article, and we shall journey together!
     Until then, stay safe, and happy collecting. hardhat2a.gif (5709 bytes)



Article Contributors


Amethyst Galleries, Inc. "Mineral Galleries"

Pete J. Dunn, Herb Yeates



Photo & Graphics Credits

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

Isaias Casanova, IC Minerals

Stan Celestian, Glendale Community College

Stephen A. Nelson, Tulane University

C. R. Nave, HyperPhysics

Alan Guisewite, Carnegie Mellon

eBay Dealers: affordableminerals, socalnevadainc, d-h-garske



© 2006  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



karissa.jpg (2366 bytes)

About the Author:  Karissa is the current President of the Delaware Mineralogical Society.  She is also a member of the Tuscarora Lapidary Society (TLS), and is an accomplished lapidarist and collector.

She also has affiliations with other mineral and fossil clubs in the eastern United States, and encourages folks of all ages on the enjoyment of our hobby.


Invitation to 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 2007, we are waiting for your suggestions.  What mineral do you want to know more about?

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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:, or tell me at our next meeting.



Past Minerals of the Month
November 2006 Mineral of the Month: Brandywine Blue Gneiss
October 2006 Mineral of the Month: Spessartite Garnet by Karissa Hendershot
September 2006 Mineral of the Month: Native Silver
August 2006 Mineral of the Month: Kryptonite
July 2006 Mineral of the Month: Azurite
June 2006 Mineral of the Month: Pyromorphite
May 2006 Mineral of the Month: Tsavorite by Karissa Hendershot
April 2006 Mineral of the Month: Variscite
March 2006 Mineral of the Month: Petrified Wood, Part II
February 2006 Mineral of the Month: Petrified Wood, Part I
January 2006 Mineral of the Month: Strontianite by Karissa Hendershot
December Mineral of the Month: Clinozoisite
November Mineral of the Month: Bismuth
October Mineral of the Month: Wulfenite by Karissa Hendershot
September Mineral of the Month: Turquoise
August Mineral of the Month: Peridot
July Mineral of the Month: Ruby
June Mineral of the Month: Antarctic Fluorite
May Mineral of the Month: Dolomite, Part 2
April Mineral of the Month: Dolomite, Part 1
March Mineral of the Month: Calcite
February Mineral of the Month: Agate
January Mineral of the Month: Fluorite
December Mineral of the Month: Pyrite
November Mineral of the Month: Stilbite  
October Mineral of the Month: Celestite   

This page last updated:  February 19, 2011 10:14:42 AM




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

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


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






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?


Collecting Adventure Stories:

"Sunny Brook Crick Goethite" by Joe Dunleavy