month, our quest is to find instances of a key Delaware rock: Brandywine Blue Gneiss.
Yes, you say that this gneiss rock is not a mineral, but a compilation of several
I agree with you. I tried to figure out a forum for rocks, and since we already have
our own Mineral-of-the-Month and Fossil
Forum, adding a "rocks only"
area might be redundant. All
this, especially since we have set a precedent for already studying some minerals along
their associated minerals and matrices.
So, why not trek around colonial Delaware a bit, and expand our horizons with a bit of
architecture, and the modern "blue rock". Let's go!
This month, we
add some local flavor to our tour. Our club's home state of Delaware is
richly steeped in some important local, national, and international history. Along
native blue gneisses, we will explore their primary use in building a nation.
Owing to the vastness of local architecture
available to us, we shall visit a few key places,
along with a brief history of quarrying and modern road building. Enjoy!
Our Brandywine Blue Gneiss has four main
mineral constituents: Quartz, Feldspar,
Pyroxene, and Magnetite. Some additional variations in our area can contain:
|Drill hole for blasting
||Closeup of Blue Gneiss minerals
Photos from the Blue Ball Project Construction Site by
to geologists of the DGS and USGS, "[t]he amphibolites and 'blue rocks' of the
Wilmington Complex were
formerly a volcanic island that existed seaward of the ancient North
American continent about 500 million years ago."
specifically, "[t]he age of the Wilmington Complex is
controversial; however, a large
mass of granitic rock, exposed in the community of Arden, was radiometrically dated and
to be approximately 500 million years old. This date suggests the Wilmington Complex may
represent the root zone of the volcanic arc that existed off the ancient North American
during Cambrian and Early Ordovician time, between 543 and 480 million years ago."
Volcanic Past: Delaware", USGS)
Freshly-blasted blue gneiss surface
Photos by Ken Casey
|| Though it may be one-half billion years old, the fresh-cut stone is a shimmering
dark blue. Upon weathering, it darkens to a
deep gray-black. This author was born right
near an outcrop, and got to happily pass his birthplace en route, in order to collect our
50-year old roadcut view of
I-95 in Wilmington
About the stone, geologically, it is believed to be about 570 million years old. It was formerly
referred to as a blue granite by quarrymen in centuries past, but is
technically a metamorphic,
banded blue gneiss of the Wilmington
Complex. The rock is composed of quartz,
pyroxene, and magnetite, and began its existence from ancient volcanoes, which preceded
Appalachian Mountains orogeny (or mountain-building event).
Over time, it recrystallized into a
solid, stable building stone, still useful in todays architecture.
& Physical Properties of the Wilmington Blue Rock
It chips, when broken. Some sharp edges
result. Specimens should be trimmed to
cuts. This blue stone is unfriendly to all but the most powerful and loud rock
Round, eroded rocks are ever plowed from farmers fields.
When hewn with
and hammers, it serves well as dimensional stone.
I would imagine that it passes modern engineering stress tests, as it is still used today
projects, when available. And, in our mild, occasionally earthquake prone area,
structures have stood throughout centuries of Delaware's episodic seismic activity.
||Our club has
samples available to teachers with limited quantity.
We may have some to offer
at our March 3-4, 2007 Show.
The major use for our
specialty Wilmington Blue Rock is as dimensional stone. Many
important historical structures were built from locally quarried rock, and still stand
Our focus here will be on
the architectural and historical uses in Wilmington, Delaware.
There are too many instances to offer in this installment. I'll leave it to you to
surf the links
I've listed to plan your own virtual and actual trips.
|Historical Masonry Wall,
||Modern dry-stack Wall, Ronald
Photos by Ken Casey
||Modern landscaping makes use of excess site
deposits for beauty and against waste.
& right: The Nemours Clinic)
(Below, left: Dry-stack Wall at the Ronald McDonald House)
Photos by Ken Casey
Blue Rocks are now known to travel two ways: one, as our local minor league baseball team
on the road; and, two, as a parcel mailed by this author to Tim and Fran Buck of the Mollyockett
Motel, on behalf of DMS. (Yes, even the ball club's logo has a rock pick hitting
some blue rocks!)
On the first account, I am not sure if Frawley Stadium incorporates
any Brandywine Blue Gneiss
in its construction, or not. I would be pleasantly surprised to know that it did.
On the second account, one masonry-quality stone with a fresh blast surface made its way
by USPS Priority Mail to a rockhound haven in Woodstock, Maine. The Bucks intend to
to their soon-to-be-constructed fireplace in a novel restaurant and renovation project.
Our club got the
opportunity to share this aspect of our clubs home state with Tim and Fran. Rockhounds from around the country
and world can visit, and in one place witness the variety of
rocks and minerals from all 50 States!
This author has
only seen such assemblages in major museums and at national monuments.
The stone might serve as a humble cornerstone on their new Crosstone Restaurants
We have also sent a smaller sample for them as a keepsake.
As one of 50 such stones, each representing a state in our nation, our blue rock will give
testimony to Delaware's rockhounding community. Tim and Fran's Mollyockett Motel lies in the
heart of Maine's rockhounding country in Oxford County. If you plan to visit:
Tim and Fran Buck
1132 S. Main St.
Woodstock, ME 04219
a Mile of the Blue Ball Project
The particular stone that this author sent to Maine has a story. Regarding the
and history of this stone, Ill tell you how and where I obtained it first. With permission from the
generous folks at the Delaware Geological
Survey and DelDOT (The Delaware
Department of Transportation), I got to collect from the spoils piles of newly blasted
road construction work at
our new mega-intersection of U. S. Route 202 and Foulk Road.
Also on the site is an historic dairy barn, called the Blue Ball, having a boundary marker
with a painted blue ball atop it, which acted as a "carriage stop" and landmark
to travelers. When
The innkeeper raised the blue ball, the coachman knew to stop. If he lowered it, the
to keep going, similar to our modern bus stop.
The barn itself served on the Alfred I. DuPont estate for some time, before sadly being
derelict for decades (40+ years in my memory). It
is now being restored to special use.
& right: Blue Ball Project
left & right: Highway Project Phase Completion)
Photos by Ken Casey
After ten years of archaeological digs, the site became open to road improvements. The state
is currently developing the surrounding area as fully-accessible parklands. To see the projects
progress, go to www.blueball.net.
It is at this opportune time that I could get permission to obtain samples for the Bucks
for our clubs educational outreach program for teachers, scouts, and fellow
for Gunning Bedford, Jr. Estate
the Bedford Estate
|Historical Marker closeup
||Masonic Lodge sign at
Photos by Ken Casey
As for our area's history, quite a few famous people lived nearby, some of whom had
their homes from this illustrious blue rock. One
such personage is Gunning Bedford, Jr. He was
instrumental in both Delawares and our nations history, by serving as a
delegate to the U. S.
Constitutional Convention in 1787. His home
stands just a few hundred feet from our collection
The centuries old trail that passes by his house, which became a nearby highway, laid
to the passing of our patriot, Caesar
Rodney, who rode his horse 80 miles almost non-stop from
Dover (our capital) to the city of Philadelphia. He was to be the first
representative to break the
deadlock vote in favor of the Declaration of Independence on July 1, 1776. He and his trusty steed
trotted over the local blue rock, and passed by farmers walls and homes constructed
of our famous
To this feat, the abutting property, which houses a shopping mall, gives tribute by being
"Independence Mall". It's veneer architecture is reminiscent of the
original building in Philadelphia.
More recently, our own Carolina League baseball team is named after this resilient
Wilmington Blue Rocks. Check out
the ball club's logo for clues to this tribute.
It is a tough stone, once quarried and used to construct many of Delawares historic
like Old Swedes Church in Wilmington. Near
the church, a half-century old blasted outcrop lines the
shoulders of Interstate 95, which also passes near Maine's doorstep, as well. No more stone quarries
exist to supply this dimensional stone
The credit for obtaining such a stone (as you know it is hard to come by these days)
to William Schenck and Tom McKenna, Geologists of the Delaware Geological Survey, Vernon
Lawton and Nick Hetrick, Project Engineers of DelDOT,
and Bruce Kay of DMJM Harris, Inc.,
Contractors, and of course, most humbly, the Delaware Mineralogical Society.
[Adapted from the letter I researched and wrote to send with with
our State's contribution.]
Local archeologists plot
the earliest evidence of man inhabiting northern Delaware as being
marked at about 12,000 years ago, during the Paleoindian Period. Though we have some
interpretation of rock use spanning up through mid-seventeenth century colonial times,
arrow and spear points, and mortar and pestle stones are the primary usages. No
Projects: Archaeology - Prehistoric Archaeology)
There may be evidence
that the earliest natives to this area employed the Brandywine Blue
Gneiss, but this author has not yet come upon it. I can suggest that some Delaware
may have witnessed the beauty of those boulders strewn across the Brandywine Creek as a
of erosional processes in ancient times.
Unbeknownst to passengers of
the Kalmar Nyckel, early Swedes who disembarked at the site
of Fort Christina on the Christina River, stepped across a large ledge of blue rock.
suggest that this was the "Plymouth Rock" of Delaware. Their foothold into
the New World was
literally here. One wonders if the thought crossed their minds to seek out this
stone for future
use, either symbolically or practically.
In fact, if
you look at our clubs website banner above, you might make out a small masted
ship on the water. That is the Kalmar
Nyckel--symbol to us in Delaware of exploration.
club motto captures this sentiment as we translate it from Latin to English. The
"Omnem Movere Lapidem" work out to "No Stone Unturned".
Since the 1630s, European
explorers and colonists witnessed some of the earliest stone
structures in use. As they tilled the soil, and loosened the blue rock fieldstones,
to accumulate excess stone. This hard-to-work rock found its way into property
and some building foundations. Some of these walls still stand today, crisscrossing
After discovering that
our blue rock lends itself well to masonry work, institutional buildings
and homes were modeled after its quaint character. The Old Swedes Church and patriot
Gunning Bedford, Jr's house in Wilmington are both constructed of this hefty stone.
The DuPont family's
endeavors at gentrifying the landscape proved successful with the use
of this resilient rock. Their business buildings made use of this locally quarried
and mills alike stood proudly, some have said haughtily, against the background of
rich history. Today, we take pride in the vast accomplishments of our early
residents. Now, many
current residents rely upon the DuPont Company's centuries old foundation to help drive
economy of Delaware, and serves to underlie Delaware's society and culture.
Most of these magnificent
structures still stand today, giving testament to the tenacity of
this stone's hold on our character. Many of the historic places may be visited by us
a museum's invitation awaiting our reply. (See below, for a list of museum links)
In the past, it was
quarried commercially in the nineteenth and early twentieth centuries. As
the most prolific, local building stone, this "Blue Granite", as it is sometimes
called, served in
the construction of various landmarks, public spaces, and utilitarian structures.
Quarries in Brandywine
Hundred, New Castle County, Delaware operated with blasting going
on within the city limits. One such hazardous event in 1902 at the Brandywine
quarry injured an Italian stoneworker. The quarry was then closed.
(Source: Stone Quarries and Beyond
by Peggy B. Perazzo and George P. Perazzo)
Modern mining in the
twenty-first century was conducted as the result of a need to remove
excess material from a large road expansion project. The Blue Ball Project
only highway construction, but reuse of abutting land, while optimally preserving our
history and architectural past.
Though most of the
project bedrock was blasted away to be reburied on site, much is seeing
its way toward some visible usefulness. Three examples are: overpass stone veneers,
institutional drystack walls, and rip-rip for project drainage areas. For further
hefty landscape boulders will grace the Delaware
Greenways and onramp overlooks, which add
modern history to the Wilmington Blue Rocks' usefulness.
This author shares the
view that with a vastly populated Delaware, no future blue rock mining
will be permitted, especially that done by blasting. So, if you have a good sample
Blue Rock--hold on to it! Show it to others to educate them about our past.
State of Delaware Division of Historical
& Cultural Affairs
Historical Society of
Brandywine Creek State Park
The Wilmington Blue Rocks--Delaware
Geological Survey (DGS)
The Hagley Museum and Library,
Old Swedes Church, Wilmington, Delaware
DelDOT Projects: Archaeological
Exploration and Historical Preservation in Delaware
Delaforum's Blue Ball Photo Album
The Mollyockett Motel, Woodstock, Maine (Blue
Rock in Fireplace masonry)
Department of Natural Resources & Environmental Control (DNREC)
Here is where DMS Members can add their nice
Gneiss photos to share with us.
Until Next Time
We hope you have enjoyed our pleasant visit to Brandywine Blue
Gneiss. Please join
us next month, for another article, and we shall journey together!
Until then, stay safe, and happy collecting.
United States Geological Survey Cascades Volcano Observatory, Vancouver Washington
I would like to gratefully acknowledge the generous contributions of our fellow Gneiss
collectors, authors, curators, professionals, and club members who made this
work possible. Thanks.
© 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
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
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,
graphics. Use of all other credited materials requires permission of each
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
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.
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: firstname.lastname@example.org.