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                           Mineral of the Month--November 2007

                              Delaware Beryl

                                                         Beryllium Aluminum Silicate

                                                         Be3Al2(Si3)Oor  Be3Al2Si6O18


                                        "Delaware Beryl"

                                              By Ken Casey

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

deflag.gif (4102 bytes)
        Delaware State Flag

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


 Beryl is uncommon in Delaware...


...and aqua is it's hue!

(Top): Delaware Beryl, Wilmington, Delaware
Photo by Ken Casey 2007




     Hello again, friends!  This month, our Mineral-of-the-Month takes us back up to Woodlawn
Quarry in historic Delaware and to one railroad stop.  

     This trip will be a brief one, though, as our state has only two known locations for Beryl. Our
local weather forecast shows sun with a chill in the air, so bundle up, and
Let's go!




     What do we know about Delaware Beryl?  Well, it is a rarity found in our northwestern New
Castle County piedmont granite.  Not really mined in Delaware for it’s beryllium, it was cast aside,
or ground down with it’s host feldspar for use in porcelain and ceramics.

     Most beryl has been found at the historic Woodlawn Quarry in Wilmington, Delaware.  The
variety here is aquamarine--though not of gem quality.  Usually, it occurs a blebs in the granite,
and sometimes as poorly-formed hexagonal crystals.  Some light green subhedral crystals do
also occur.

     Just to the north of this locale is the Pennsylvania beryl found as nice, sometimes gemmy,
crystals in Chester and Delaware Counties.  Perhaps there are some gemstones hiding deep
below the ground in Delaware, yet to be found.  As most land is private, and mining prohibited,
only road construction might reveal a future source.  Will they build a superhighway in rural north
Wilmington west of Route 202?  Maybe our great-grandchildren might tell us, if urban expansion
continues.  Though, conservation is most likely the outcome late into the 21st century.

So come on along, and let’s enjoy a brief virtual fieldtrip--Enjoy!


Why Delaware Beryl?


      Why not?  I asked my fellow club members at our October 8, 2007 general meeting
whether they wanted to know more about Delaware Beryl or Delaware Mica first.  Guess
which one they picked?  Please do join us!


     So, grab your walking
sticks, and let's hike!


Delaware Beryl locale, Woodlawn
Quarry Trail, Wilmington, Delaware
(Photo by Ken Casey)



What's in a name?


     "Beryl" is derived from the ancient Greek word "beryllos", meaning "the precious blue
green color of sea water" stone.  Later, the term was applied to only beryls.  The term is so
ancient, that the IMA deems it "prehistoric" in origin.


     We have multiple varieties of beryl found around the globe, including emerald, morganite,
bixbite, goshenite, heliodor, and aquamarine.   Delaware's "aquamarine" is a literal Greek
translation for "seawater".


Chemistry & Science

We can find many varieties of beryl in the world.  We can even make synthetic beryl.

     Beryl in The First State is all-natural, though.  Delaware's beryl is Aquamarine.  Beryl
is a beryllium-rich cyclosilicate or tectosilicate of chemical formula Be3Al2Si6O18.  

     On the Moh’s Hardness Scale, it ranges from 7.5-8.

     It's tightly-bonded circular molecular structure and outward hexagonal shape make it an ideal candidate for surviving as crystals over the eons for us to enjoy.  We may find sizes from near microscopic to several feet long.  The Great State of Maine boasts the larger of the two sizes; whereas, Delaware's can range from about 1-3 inches in length at best.

     Some of the gemmiest aquamarine comes from Brazil; whereas, the largest crystals in the world are found in far
away Madagascar.

     Imagine if we had such gargantuan crystals in Delaware?
Hexagonal Aqua Crystals
Drawings by Ken Casey

     Beryl is rare in pegmatites.  Tourmaline is a more common constituent.  Beryllium
seems to occur less often in crustal rocks, than does the more lithium-rich tourmaline.  It
is interestng to note that on the Periodic Table of Elements, the order of abundance
begins with Hydrogen, Helium, Lithium, then Beryllium.  The sequence tapers down to
the rare-earth elements (REEs).

     Prized as a gemstone since time immemorial, beryl occurs in a vast array of colors:
blue, green, yellow, red, pink, and clear.

     Delaware's aquamarine color derives from Iron (Fe++).  The greener variety comes from
mixtures of ferrous (Fe2+) and ferric (Fe3+) Iron as impurities of its crystal lattice structure. 
Yes, even the oxidation state of Iron can affect the degree of color!

     True emerald, on the other hand, has it's green based upon Chromium (Cr+++). 

  (Source: Gems and Gem Materials Course, Jim Banfield, UC Berkeley

Delaware Aquamarine Beryl in feldspar  (Photo by Ken Casey) 


     One could lap Delaware Beryl, but its typical coincoidal fracture of sub-gem quality
material might cause it to chip or shatter when a vibrating abrasive wheel is applied.  I
know from personal experience as a jeweler, that one should avoid cleaning a faceted
beryl gemstone in an ultrasonic bath; it's brittle nature allows microfractures surrounding
inclusions to crack the stone, thus ruining one's client's jewelry.  (I actually learned this
lesson in jewelry school first.)

     On the other side of the usage spectrum, metal refiners choose to crunch beryl
crystals to extract our prime source of beryllium.  Delaware's aquamarine is not used for
this purpose.


 Delaware Beryl Locale and green beryl in pegmatite  (Photos by Ken Casey)


Some Delaware Beryl Geology

     Two exposures of beryl in granite are known to exist New Castle County, Delaware. 
One appears at the Woodlawn Quarry, the other occurs along a railroad cut.

       Around the Mt. Cuba railroad cut of a bygone era, is a vein of a coarser-grained granite pegmatite in northern Delaware.  This vein is composed of feldspars, quartz, and black mica.  Schorl and light green beryl have been found here in the past.

(Source: Delaware Piedmont Geology by Margaret O. Plank and William S. Schenck)

     A blue-green beryl area straddles a few miles over the Delaware-Pennsylvania border.  Covering northern New Castle County in our state to Chester and Delaware Counties in neighboring PA.
(Above): Generalized Delaware-Pennsylvania Beryl Area Map
Map by Ken Casey 2007

     Let's visit the Woodlawn Quarry locale.  Follow me.  I’ll guide us with our favorite 
DGS's GeoAdventure directions.

       We'll cross Ramsey Run and climb
a curving trail uphill, until we reach the
first right turn.  All around us, we can
see eroded century-old mine tailings
strewn about the forest.

     Once a thriving quarry, it is now a
protected wildlife sanctuary, run by
the Woodlawn Trustees, whose
permission we need to hike here.

     It's a good thing we brought our
walking sticks, and wore our hiking
boots, as safety is important on any

     Now we can circle round to an
unpretentious mud hole--but wait! 
It's not just a water-logged ditch,
it's an abandoned quarry gone to
nature.  Let's get a closer look!
Eroded tailings trail through the forest (Ken Casey)    

     When I first came upon this site, this author was searching for a big hole in the
ground, or even a broken wall or ridge that seemed uplifted from the forest floor. 
But, no.  What is here is a smaller scale mine than what I had expected.

       Water-filled quarry pit at ledge   Mica on ledge soil is slippery--step back, please.
(Photos by Ken Casey)

     Slightly disappointed at first, I realized that several decades of disuse
left nature to bring back a succession forest.  Some trees that span the site
are large, and nearly a century old!  Mammoth maples, oaks, and poplars have
rooted themselves in quartz, beryl, and feldspar tailings!

     It is this dangerously steep and muddy hole that remains.  It marks the center
of activity here.  Let's back away from the slippery micaceous ledge, and have a
closer look at our desired beryl. 

     Massive beryl can be mistaken for quartz, as pale green or blue blebs in our quartz
matrix.  The color-corrected digital photo below shows the contrast between the grains
of clear and smoky quartz and the more colorful beryllium aluminum silicate.

Blue-green blebs of aquamarine beryl in graphic granite  (Photo by Ken Casey)

     It seems the fall line geology, as it sits between the Piedmont and the Coastal Plain, is
similar.  Both Delaware and Georgia, for example, have some granite pegmatites that contain
blue-green beryls.  In fact, all along this boundary, we can find instances of beryl geology.

  (Source: Geology of Georgia by Darlene Cooper, Columbus State University)                       

   During the Taconic Orogeny (about 270 mya), scientists believe that granitic plutons
creating beryl crystals, as the Earth's crust moved on its way to continental collision.

(Source: USGS "America's Volcanic Past")

     This is how the Mt. Cuba vein most likely formed.  One good way that we could visit
the beryl here is by taking a ride on the Wilmington & Western Railroad.   We'll take the
"club" car.  Let's board at Greenbank Station, which happens to be across the street
from our clubhouse at Greenbank Mill.

     As the train stops at the Mt. Cuba Picnic Grove area, we'll detrain.  After a tasty lunch,
we will walk over to the geology, and have a look.  I didn't get any pictures last trip, so you'll
have to whip out your camera.  Maybe you can share them with us.

     On our return trip, let's look at some photos of Delaware Beryl.  After that, why not
check out the links and museums below.

            Beryl       Aquamarine      University of Delaware Beryl virtual tour



Color-corrected photos of green and blue beryl in matrix from Delaware
(Photos by Ken Casey)


Two Museums of Note

     This month's museums are the Virginia Museum of Natural History and the Paul R. Stewart
Museum.  Both house and display area mineral collections.  And, each are located in nearby
Virginia and Pennsylvania, respectively.

     The VMNH, located in Martinsville, hosts approximately 5,000 pieces and 70,000 drill cores. 
How many of these are beryl, I do not know.  You may have to just visit them, and explore the
vast collection on your day off.  They are associated with the Smithsonian Institution, and do
offer some nice mineral and fossil Field Trip Adventures.  Yes, yet another fun activity to check
out, after you finish our virtual fieldtrip today!

     The Paul R. Stewart Museum is located on the campus of Waynesburg University aptly in
Waynesburg, PA.  The university staff have opened their museum to the public, with the best
access during the academic year.

     The PRSM offers collections to view of early pottery, fossils, and minerals.  Check out
their sample online specimens.  It's best to check their website or call before visiting.




     Delaware beryl has only an interest to collectors and those of us who enjoy the study of
our local geology.

     Scientists study it, though it is a rarity in our area.  Perhaps you will find a use for our
Delaware Beryl.




Beryl (Aquamarine) (UC Berkeley)

Woodlawn Quarry: A GeoAdventure in the Delaware Piedmont

Delaware Minerals List at

Geologic Time Scale (USGS)


Members' Gallery

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



Until Next Time

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


Marchex, Inc., World Flag Database


2007 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 2007-8, we are waiting for your suggestions.  What minerals 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, 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
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 10:15:07 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