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                           Mineral of the Month--Novber 2008

                              Delaware Kyanite

                                                       Aluminum Silicate with Fluorine





                                        "Delaware Kyanite"

                                              By Ken Casey

Why Delaware Kyanite?
What's in a name?
Chemistry & Science
Some Kyanite Geology
Two Museums of Note
Members' Gallery
Article Contributors
Photo & Graphics Credits
Suggested Reading
Invitation to Members
Past Minerals of the Month

Delaware State Flag

Image courtesy of Marchex, Inc.
2007, World Flag Database


Unlike Utah's gems...


...Delaware Kyanite occurs!

Delaware Topaz, Whittington's Sand Pit, Delaware
On display at the Iron Hill Museum, Newark, Delaware
Photo by Ken Casey 2008




     "See you in September" was our sign-off phrase after our club's June Picnic in Delaware, fellow
rockhounds!  This month, our
Mineral-of-the-Month takes us to two former outcrop locales in New
Castle County's Piedmont Province, and stops to two local museums to see our Fluorapatite! 

     Summer is winding down, yet after some downpours from tropical storm Hanna, a warm and
pleasant day greets us for our fieldtrip today, so
Let's go!




     Local rockhounds know of a place just across the state line from Delaware into Pennsylvania. 
It is known as Prospect Park, not far off of I-95.  Excellent examples of blue-bladed Kyanite have
been found over the years.

Who would have thought that Delaware has had its share of Kyanite finds?  The folks at the Iron Hill Museum have!  They have on display Kyanite from Hare’s Corner, Dixon’s Quarry, and Felton, Delaware.  Why not visit them, and take a look for yourself.  I have, and they are good examples.


Since these areas have been built over in recent decades, it may no longer be possible to prospect for Delaware Kyanite at these specific locales.  That doesn’t mean that one can’t find samples upon new construction digs, and other such projects.


We Delawareans know that our Official State Mineral is Sillimanite, a trimorph of the series Kyanite-Sillimanite-Andalusite. So, why wouldn’t we find all three of these related minerals in the First State?


Well, varying degrees of temperature and pressure, during these mineral’s formation events, are the cause.  The metamorphism responsible seems to have enriched Delaware in Sillimanite, and Pennsylvania in Kyanite.  (Of course, the minerals had already formed.  We drew the political boundaries later.)


How do we know we have found a sample of Delaware Kyanite?  Well, by the recognizable long, blue blade crystals.  Kyanite is almost unique in its color and crystal form, so a good field ID can be made.  Sillimanite has gray-white-tan blades.


Upon study, Kyanite’s chemical formula, Al2SiO5, is shared with Sillimanite and Andalusite—same formula, different form.  Cool, huh?  Perhaps you could make a personal rockhound quest to find all three trimorphs in Delaware.


Scientists use data of this trimorph’s formation in activity models in thermodynamic study.  Data can be employed show this process in a phase diagram.  The metamorphic processes of these three minerals is a classic example of mineral formation, upon which geology students build their basic understanding of petrogenesis.  Come back in December for another Delaware mineral.



Photo captions:


delkyanite1.jpg “Delaware Kyanite, Dixon Quarry, DE; Iron Hill Museum,


     So come on along, we have a Delaware Fluorapatite fieldtrip to make!





Why Delaware Fluorapatite?


     Delaware Fluorapatite  please do join us!

     Pale blue mineral veins hide in some of New Castle County’s Piedmont pegmatites—they
are the Delaware mineral Fluorapatite.  It is commonly found in most igneous rocks, especially
pegmatites and hydrothermal veins.

     A member of the Apatite family, this Calcium fluophosphate has chemical formula Ca5(PO4) 3 F,
and crystallizes in the Hexagonal System.  In Delaware, it forms veinlets and sometimes as small

     It is difficult to find collecting locales, as most areas have been covered over by housing
developments in the north, though DGS core samples and sediment studies have produced
specimens statewide.  Macro specimens have been found at two historic locales: the Brandywine
Quarry, where Apatite crystals were found, and Fluorapatite vein remnants at the Ramsey Run Mine
Dump—both in Wilmington.  The Delaware Geological Survey has a sample on display in the Newark
office.  (See: photo)

     We all carry some Apatite with us daily.  Either in our teeth or bones, Calcium phosphate (as
hydroxyapatite) supports us daily, as we rockhound our First State.  If our dentist recommends
fluoridated water or toothpaste, he or she might expect its application to strengthen teeth by converting
plain Calcium phosphate into a harder fluorapatite.  And, harder teeth resist decay. 

     In essence, as Delawareans, we might be creating new Fluorapatite to enjoy daily.



What's in a name?   





Chemistry & Science





Some Delaware Fluorapatite Geology







Two Museums of Note

     Our MOTM format will continue to offer us information on two places we can visit to learn more
about minerals, such as this month's Iron Hill Museum, which contains several specimens of our
Delaware Fluorapatite.

     Our second museum 



     As Delaware Fluorapatite




Delaware Minerals List at



Members' Gallery

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



Until Next Time

     We hope you have enjoyed our historic visit to Delaware Fluorapatite.  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

Delaware Piedmont Geology by Margaret O. Plank and William S. Schenck, DGS



Photo & Graphics Credits

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

Arthur Koch, DMS Member, B. S. in Geology, Mineral Photographer

Marchex, Inc., World Flag Database

Delaware Piedmont Geology by Margaret O. Plank and William S. Schenck, DGS

Nenad Spoljaric and Robert Jordan, Thomas E. Pickett, Delaware Geological Survey

Physiographic Map of Pennsylvania, Pennsylvania Geological Survey

Photomicrograph by UCLA's Petrographic Workshop

Gem Trails cover by Mark Webber

2008 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:

Delaware Piedmont Geology including a guide to the rocks of Red Clay Valley
by Margaret O. Plank and William S. Schenck


KEN.JPG (31503 bytes)

   About the Author:  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:

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 2008, we are waiting for your suggestions.  What minerals 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, and suggestions by our members, 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
September 2008 Mineral of the Month: Delaware Topaz
August 2008 Mineral of the Month: Charoite
July 2008 Mineral of the Month: Sugilite
June 2008 Mineral of the Month: Larimar
May 2008 Mineral of the Month: Delaware Hornblende
April 2008 Mineral of the Month: Delaware Biotite Mica
March 2008 Mineral of the Month: Delaware Pegmatites
February 2008 Mineral of the Month: Exotic Pegmatites
January 2008 Mineral of the Month: Delaware Quartz, Part 2
December 2007 Mineral of the Month: Delaware Muscovite Mica
November 2007 Mineral of the Month: Delaware Beryl
October 2007 Mineral of the Month: Delaware Quartz, Part 1
September 2007 Mineral of the Month: Delaware Garnet: Almandite
August 2007 Mineral of the Month: Schorl (Black Tourmaline)
July 2007 Mineral of the Month: Rubellite
June 2007 Mineral of the Month: Elbaite 
May 2007 Mineral of the Month: Delaware Feldspar, Part 2 
April 2007 Mineral of the Month: Delaware Feldspar: Orthoclase
March 2007 Mineral of the Month: "The Colors of Fluorite"
February 2007 Mineral of the Month: Pennsylvania Fluorite
January 2007 Mineral of the Month: Sillimanite
December 2006 Mineral of the Month: Hedenbergite by Karissa Hendershot
November 2006 Mineral of the Month: Brandywine Blue Gneiss
October 2006 Mineral of the Month: Spessartite 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   


Comments and questions:

This page last updated:  February 19, 2011 10:15:29 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