of the Month--Novber
Aluminum Silicate with Fluorine
By Ken Casey
"See you in
September" was our sign-off phrase after our club's June Picnic in
rockhounds! This month, our
takes us to two former outcrop
locales in New
Castle County's Piedmont Province, and stops to two local museums to see
Summer is winding down, yet after some downpours from
tropical storm Hanna, a warm and
pleasant day greets us for our fieldtrip today, so
rockhounds know of a place just across the state line from Delaware into
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
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.
delkyanite1.jpg “Delaware Kyanite, Dixon Quarry,
DE; Iron Hill Museum,
So come on along, we have a Delaware Fluorapatite fieldtrip to make!
Delaware Fluorapatite please do
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
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?
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
Our second museum
As Delaware Fluorapatite
Delaware Minerals List
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.
would like to gratefully acknowledge the generous contributions of our
Garnet enthusiasts, collectors, authors, curators, professionals, and
club members who
made this work possible.
Arthur Koch, DMS Member, B. S. in Geology,
Nenad Spoljaric and Robert Jordan, Thomas E. Pickett,
Delaware Geological Survey
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
Delaware Piedmont Geology including a guide to the rocks of
Red Clay Valley
by Margaret O. Plank and William S. Schenck
About the Author:
Ken is current webmaster of the Delaware
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
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
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.
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
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
will be a surprise.
For 2008, we are waiting for your suggestions.
What minerals do
want to know more about?
Most of the
Mineral of the
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:
email@example.com, or tell me at our
the Fossil Exposures in the Chesapeake Bay Area" presented by Dr. Lauck
General Club Meeting:
We are meeting at
*Show Committee Meeting, April or May, 2013
*New Home/Lapidary Committee, 2013
*Board Meeting, April, 2013
Next Field Trips
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
also commemorates our 50th Show!
It's shiny, yellow, and
is a symbol of 50 Years!Can you guess?
Brook Crick Goethite" by Joe Dunleavy