In a two-part series (this month and next), we will explore Dolomite as our
More specifically, in part 1, we will explore Dolomite crystals and Dolostone. In
part 2, we will
embark on a journey to New York State of the famous Herkimer Diamonds and
matrix host. Uses from crushed stone to recreating over karst topography will be
Being in the Calcite Family, Dolomite offers remarkable assemblages
of crystals from its
related limestone-dolostone host. Of course we will begin with dolomite science.
Then, we will
touch upon the geologies of both Pennsylvania and New York States, as they relate (from
to east) to Niagara Falls, Herkimer County, New York, and Eastern Pennsylvania. We
compare a few dolomites from around the world from select locales. Then, from a
ecotourism to field trips to crystals and collecting, we will travel from west to east,
at our clubhouse in Wilmington, Delaware. So grab your hardhat, and lets embark!
Well, it looks like everyone is present and accounted for. Everyone has
their safety gear,
and we have all met up on time at the Schoellkopf
Geological Museum in Niagara Falls, New
York. Lets go!
Our first stop is here at
the museum to learn of the basic geology of the Niagara Gorge.
Next, we will explore the riverbank on a special trail, then arrive back at the museum to
to our next spot, Herkimer County, New York.
|Niagara Falls, Photo by Niagara Falls State
||Tan dolomite crystals, Herkimer, New York
Dolomite, which is named for the French
Mineralogist Deodat de Dolomieu, consists of
calcium magnesium carbonate or CaMg(CO3)2.[xiii]
Pure dolomite contains 54.28 percent
calcium carbonate and 45.72 percent magnesium carbonate.[xiv]
Concerning dolomites crystallography,
crystals typically form rhomobhedral (Hexagonal
System), curved saddle-shapes in groups. Generally occurring as pink pearl spar, it
occur in clear, white, gray, tan, or black, depending on its formation with related
forming cation substitutions. For example, with a substitution of iron (Fe) for
brownish ankerite, Fe(CO3)2 crystals will form.[xv] Our club has collected such ankerite
crystals from eastern Pennsylvania.
With a relative hardness of 3.5-4, its
differentiation from calcite can be determined by
|Brown ankerite on gray dolomite boulder
from Phoenixville, PA, nearly cabinet-ready
Photo by Ken Casey ©2005
||Rhombohedral Dolomite Crystal
Photo by Stan Celestian ©2005
|Dolomite (Hexagonal) Rhomb
Steep Rhomb & Base
in Dolostone Matrix
(Drawings by Ken Casey © 2005)
|Rhombohedral Dolomite Crystal
||Clear and Milky Calcite, Pink
and Purple Fluorite vug, Kurtz Quarry
by Stan Celestian ©2005
by Ken Casey ©2005
Dolomite and dolostone are used for nearly all
the same purposes as calcareous
limestone; however, the additional magnesium content allows other uses. In the case
dolomite rock or dolostone, the calcite, quartz, and feldspar constituents
a tougher dimensional stone.
The most important use of dolostone for
which limestone cannot be substituted is in the
manufacture of refractory dolomite and in the preparation of heat-insulating materials.
Limestones and dolostones high in silica are suitable for the manufacture of mineral or
wool for insulation.[i]
A source of magnesium metal and magnesia.
Also used in as an aggregate for cement
and as a flux in blast furnaces. When dolostone is used a flux, the resulting slag can be
reused for light-weight aggregates and the like, because dolostone slag does not
in water as limestone slag does.
Dolomite is used in manufacturing cement, in
addition to being an ornamental stone.
Dolomite is a major ore from which magnesium is separated, which in turn is burned for use
in a variety of lighting applications, such as photography and pyrotechnics.[ii]
Dolomite is used to make magnesia, which has
important medicinal applications.
Dolomite specimens from the Picher, Oklahoma area are very popular among mineral
collectors and dealers. The clear transparent specimens from Spain are rare and unusual,
and are in high demand by collectors.
Dolomite Rock is used as an ornamental and structural stone, and
for extracting certain
metals from their ores. It
is useful in the chemical industry in the preparation of magnesium
For example, a western Pennsylvania company,
Moore & Moore in Portersville, hauls
and spreads both dolomite and calcium limes for customers.[iv]
On the other side of the state, [t]he
Middle Cambrian Ledger Formation in eastern
Pennsylvania is a high purity, single-stage-sintering dolomite. It yields high quality,
bonded, environmentally clean, doloma bricks for steel, cement and lime industries
recreation one might attempt to traverse the Italian
Dolomite Range of mountains. According to authors Kohler &
Memmel in their book Classic Dolomite Climbs, a mountaineer
could ascend multi-peak traverses, long middle-grade classics,
multi-pitch high-peak challenges & free-climbing testpieces.[vi]
Even coal-mining reclamation in the United States can
from the presence of dolomite. In the coal-mining regions of
Pennsylvania, a process called alkaline addition is argued to curb
the acidity leaching from mine tailings into the environment.
The addition of alkaline
material, usually a limestone-derived waste product, to surface
mine backfills can be an effective method of compensating for overburden that is naturally
deficient in neutralizers.[vii]
Carbonate minerals play an extremely
important role in determining postmining water
chemistry, as both calcite and dolomite will neutralize acid, and potentially
In eastern Pennsylvania, dolomite/calcite rich
Pleistocene glacial till has been deposited
to aid in the process. In summary, glacial overburden can be beneficial in
mine drainage if it is calcareous. Because of the small grain size, unlithified nature,
source of carbonates in glacial sediments, the NP determinations of glacial overburden
probably more accurately reflect the ability of the glacial sediments to prevent and
acid mine drainage than is sometimes the case with bedrock overburden.[viii]
Since a clean groundwater source is important
to both nature and man, the protection
of aquifers and our karst topographies is of paramount importance to our survival.
and dolostone, by their very nature, erode via the hydrologic cycle, from a mild, acidic
This runoff over our watersheds, seeps into the bedrock to promote the formation of caves
and subterranean rivers.
Dolomite and dolostone also serve us above
ground, as well. The Niagara Gorge and
Escarpment development over the last few thousand years has yielded a grand, natural
phenomenon known as Niagara Falls. A popular tourist attraction spanning the U. S.
New York and Ontario, Canada, these water features arouse awe, wonder, and hydroelectric
The famous twentieth-century scientist, Nicola
Tesla, designed the power plant that still
serves the electricity needs of two nations. In fact, the flow of river water over
the falls is
regulated to provide optimum power and tourist satisfaction over a day-night cycle.
This author learned all this while visiting the
falls and the Schoellkopf
in Niagara Falls, New York. Situated right on the river gorge, this museum
the makeup of the falls. For more on the lore of the falls, other popular museums
found in the area.
In our clubs area, many organizations are
making a positive impact to preserve our
supportive karst. For example, in 2004, the National
Fish and Wildlife Foundation has
granted funds to the Bucks County Chapter of Trout Unlimited will prepare and
a habitat restoration plan for Mill Creek. The headwaters of the 21 square-mile Mill Creek
watershed are situated within Cambrian limestone and dolomite geology, creating ideal
conditions for a significant cold water fishery.[ix]
Many nature preserves around our country and
the world rely on the basic karst
topography to support wildlife. In addition to our U.
S. National Park Service, devoted to
conservation, as mentioned in our March 2005 Mineral-of-the-Month article on calcite, three
such organizations around the world stand out to me as fine examples. They are: The
Missouri Department of Conservation (for education), the Botsalano Game Reserve
South Africa (for conservation), and the U. S. Fish
& Wildlife Service (for its endangered
David Bruns, Conservation Education Consultant in his News from
newsletter article, We Have Karst, promotes his state by offering
that [s]edimentary rocks
including limestone and dolomite dominate the geology of Missouri.[x]
Missouri cave and karst info: http://www.conservation.state.mo.us/conmag/2000/03/1.htm
The Botsalano Game Reserve, formerly a cattle ranch, [l]ying on the eastern edge of
Kalahari, the area consists mainly of acacia and karee woodlands and extensive grasslands
dotted with olea clumps which like the dolomite geology.[xi]
Our U. S. Fish & Wildlife Service
touts that [t]he Ozarks region of northern Arkansas,
northeastern Oklahoma, and southern Missouri is known for its brilliant autumn foliage,
forested slopes, whitewater streams, icy cold springs, and caves. Springs, sinkholes, and
caves are just a few examples of the types of karst features commonly found in the
and dolomite geology of this region. The term karst is derived from Krs, a place in
known for limestone geology (Elliott 2000). In the 17th century, eyeless white salamanders
occasionally washed up out of caves in that region, and inhabitants believed they were the
young of dragons that lived in the earth (Culver et al. 2000).[xii] The
notion of draconic
troglodytes is intriguing, eh?
Sea water, high in magnesium, flows through porous limestone
and replaces some of the
calcium with magnesium turning limestone into dolostone.[xvi]
Therefore, some marine fossils
may be found, especially in the grayer materials around the Great Lakes area.
Limestone is composed of material derived
by both chemical and biological activities. The
particles of sediment that make up a typical limestone are frequently recognizable as
fragments. By contrast, most dolostone is crystalline. Dolostone forms when
pore water is substituted for some of the calcium in the original limestone, or by direct
precipitation. Most limestones of commercial importance accumulated in relatively shallow
marine environments and are widely available for utilization. Carbonate rocks form about
percent of the earth's sedimentary strata.[xvii]
Pennsylvania Dolomite Geology
The Pennsylvania Trail of
Geology publication series, offered by the Pennsylvania
Department of Conservation and Natural Resources (DCNR), in Park Guide 15 guides
on a tour of Caledonia and Pine Grove Furnace State Parks. On a hike you could
The carbonate rock present in some of the low hillsides and valleys of South
called the Tomstown Dolomite. This rock unit is primarily gray dolomite containing
of white limestone. Also, it has a very low resistance to weathering and
thus usually results
in valleys. Iron ore found at the base of this unit was actively mined in the
you are heavy into topography and stratigraphy, you might enjoy allusion to more of
Calcite and dolomite occur in the freshwater limestones of the Allegheny, Conemaugh,
Monongahela, and Dunkard Groups. Additionally, in the Monongahela and Dunkard Groups,
calcite and dolomite are the most common carbonate minerals present in other rock
composition data for the Vanport limestone and other Pennsylvanian limestones
and dolomites are shown in Table 8.7. Data from a few Cambrian and Ordovician limestones
and dolomites, including the Valentine limestone from Centre County are included for
comparison, as these high-calcium limestones are well known for their purity and
This is just a taste
of the information online, and in books, libraries, and academic papers.
The DCNR offers many free online publications to learn more of this partially-karsted
Our local dolomite in
southeastern Pennsylvania is interspersed with limestone. All of the
calcium and carbonate families are represented here, including calcite, dolomite, siderite
and ankerite (Fe). Within these ranges over several area quarries, the rock material
can be easy to
work for freeing crystals from their vugs, or hellacious. For the quality of the
located within, the work is well worth it.
Our clubs fieldtrips have rewarded us with
magnificent crystals. Some of the best are pink
saddles nestled in clear calcite and purple fluorite. An example is from the Kurtz Quarry in
Other associated minerals, such as pyrite,
chalcopyrite, fluorite, dolomite form massively,
or as crystals, within our areas limestone and dolostone quarries. It also
occurs with apatite,
barite, gypsum, quartz, and sphalerite. This author has found some good micromount
sphalerite and clear quartz crystals in mini-vugs of the Franklin dolostone at the
Dump of the Franklin Mineral Museum,
Franklin, New Jersey.
In Sussex County, New Jersey, it occurs with
358 zinc ore-related minerals, most notably,
near the Franklin Zinc Ore body of franklinite, willemite, and zincite.[xx]
Beyond our clubs general collecting range
lies numerous locales that popularize this vuggy
mineral. One of our March Show
vendors, Isaias Casanova of IC Minerals, has
some of his dolomite collection photos for us to enjoy.
To see more Binkley-Ober
Quarry Field Trip dolomite vug pictures, visit our field trip pages.
Michigan Kona Dolomite cabbing rough, slabs, or
tumbling rough comes from Kona Hills
South of Marquette, Marquette County, Michigan. This pink and red, crystalline rock
is a major
source for lapidaries. Two other popular uses for Kona are spheres that
resemble petrified wood,
and as gemstone handles for art knives.
Mexican picture dolomite resemble banded agate,
whereas, Wisconsin druzy dolomite looks
like reddish-gray quartzite, but softer, of course. Mottled tan, pink, and purple
makes up Forest
County, Wisconsin dolomite rough.
The countries of Switzerland, Germany, Italy,
Morocco, and Spain produce some nice material.
Until Next Time
If you feel like trekking home before our next
installment and field trip to Herkimer, New York,
please do. We will meet back here on May 1, 2005. For those of you who want to
go right ahead. There are many resources to explore on this page and links to many
the time you have explored them all, it will be time to convene for our Herkimer Diamond
Until then, stay safe, and happy collecting.
Peninsula Geological Society (Newsletter is called The Pink Dolomite Saddle)
Falls State Park, Niagara Falls, New York
Thorold Quarry, Ontario, Canada (pink dolomite
Isaias Casanova, IC
United States Department of the Interior, Bureau of Land Management,
National Park Service (NPS Photo)
I would like to gratefully acknowledge the generous
contributions of our fellow calcite
collectors, authors, curators, professionals, and club members who made this
work possible. Thanks.
Isaias Casanova, IC Minerals
United States Department of the Interior, Bureau of Land Management,
National Park Service (NPS Photo)
Niagara Falls State Park, Niagara
Falls, New York
All contributions to this article are covered under the copyright protection of this
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 information
contained herein responsibly. DMS is not responsible for misuse or
accidents caused from this
Pennsylvania Trail of Geology
11: Carbonate reservoir characterization Geophysical aspects for TGP4177 by
Professor Helge Langeland, Norwegian University of Science and Technology, Trondheim,
A Volume in Honour of Dolomieu (Special Publication of the International
Association of Sedimentologists) by Bruce Purser, Maurice Tucker, Donald Zenger
white crystal dolomite deposit near Gouverneur, New York" (Report of investigation -
New York State Science Service, University of the State of New York) by John James
and stratigraphy of the limestones and dolomites of Dauphin County,
Pennsylvania", (Pennsylvania. Topographic and Geologic Survey. General geology
report G44) by David B. MacLachlan
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.
Limestone and Dolostone. Arkansas
Geological Commission. Little Rock, AR.
31 Mar. 2005
Cassidy, Patrick (webpublisher). Webster's 1913 Dictionary.
Revised Unabridged Dictionary Version. C. & G. Merriam Co. Springfield, MA. Under
the direction of Noah Porter, D.D., LL.D. 31 Mar. 2005
Friedman, Herschel. The Mineral and
Gemstone Kingdom: Dolomite. 2000.
31 Mar. 2005
Moore & Moore Hardware. Portersville, PA.
Lime Spreading. 15 Dec. 2004.
31 Mar. 2005
Furman, F.C.; Gregg, J.M.; Ablin, V.C.; Moore, R.E.
Geological factors controlling
the utility of refractory dolomite: The Cambrian Ledger Formation dolomite, a case
study. Energy Citations Database, United States Department of Energy, Office of
Scientific and Technical Information, Washington, D. C. 1 Mar. 1993 (publ.)
13 May 2001 (system entry). 31 Mar. 2005
Wildernet Guidebook & Map Store (online
listing): Classic Dolomite Climbs, Kohler
& Memmel. 31 Mar. 2005
Smith, Michael W.; Brady, Keith B. C.. Pennsylvania
Department of Environmental
Protection, Harrisburg and Phillipsburg, PA. Coal Mine Drainage Prediction and
Pollution Prevention in Pennsylvania: Chapter 13: Alkaline Addition. 31 Mar. 2005
Brady, Keith B. C.; Hornberger, Roger J.; Fleeger, Gary. Pennsylvania
Environmental Protection, Harrisburg and Pottsville, PA. Coal Mine Drainage
and Pollution Prevention in Pennsylvania: Chapter 8: INFLUENCE OF GEOLOGY ON
POSTMINING WATER QUALITY: NORTHERN APPALACHIAN BASIN . 31 Mar. 2005
National Fish and Wildlife Foundation. 2004
Delaware Estuary Grants Program.
31 Mar. 2005
Bruns, David. Making Tracks, vol 3, number 9.
News from Rockwoods
Reservation: We Have Karst. Wildwood, MO. Sep. 2003. 31 Mar. 2005
North West Parks and Tourist Board. North West Province:
Botsalano Game Reserve: Central Region: Map. 2005. 31 Mar. 2005
Nilius, Raye; Graening, Geo. Ozark
Underworld. Endangered Species
Bulletin. Sep./Oct. 2000, vol. XXV, number 5. (p. 14) 31 Mar. 2005
Amethyst Galleries, Inc. Dolomite.
1998. 31 Mar. 2005
Carbonates: Dolomite, Ankerite, Barytocalcite. Kentucky
University of Kentucky, Lexington, KY. 31 Mar. 2005. 31 Mar. 2005
Prospectors and Developers Association of Canada
PMACMM). Rock Identification Guide: Dolostone. 2005. 31 Mar. 2005
Bureau of Topographic and Geological Survey.
Pennsylvania Trail of Geology:
Park Guide 15: Caledonia and Pine Grove Furnace State Parks. 31 Mar. 2005
Yeates, Herb. The Franklin Mineral Museum, Franklin, NJ. The
Confirmed Mineral Species from Franklin-Sterling Hill. 23 Mar. 2005.
31 Mar. 2005