Preface Introduction Chemistry & Science Crystals Geology Uses Lapidary Links Endnotes Article Contributors Photo & Graphics Credits Suggested Reading Webliography Invitation to Members Past Minerals of the Month			Clinozoisite Crystal, Chester Emery Mines, Chester, MA Photo by & Courtesy of Scott Whittemore  ©2005
		Clinozoisite:...
		...'What gem hides behind its useful properties?'

Preface    

     This month’s Mineral-of-the-Month might just have us in awe.  It’s a relatively common
mineral: Clinozoisite.  You might ask, ‘What is so special about it?’  Well, it has some newly
patented uses, and serves as an exotic gemstone, rarely exceeding 5-carats, when faceted.[i]

     Yes, these crystals pull double-duty—more so, than the old guidebook’s usefulness rating
of “Of interest to scientists and collectors only” statement would have us believe.

Introduction

     We will see some of our crystals on this installment through the lens of mineral photographer,
Scott Whittemore.  Get ready to feast your eyes on some spectacular crystals from the U. S.
and beyond.  (See some of his other mineral photographs at his website:
Scott Whittemore’s Mineral Photomicrograph site.)

What’s in a Name?

     Clinozoisite is named after its Epidote series companion, Zoisite.   “Clino-“ derives from
the Greek “klinein” (to incline).  It refers to the inclined axis of the monoclinic crystals.[ii] 
The original “Zoisite” was named after Baron von Zois.[iii]

Chemistry & Science

     As a hydrous calcium aluminum silicate in the Epidote group, clinozoisite is Sorosilicate,
which crystallizes in the Monoclinic System.  Other major members of the group: Zoisite, Epidote,
Piemontite, and Allanite, all form in the Monoclinic Crystal System, except Zoisite.  It is the
only Orthorhombic member.  In fact, that is the main distinguishing feature between Zoisite
and Clinozoisite, which may be determined by optical mineralogy.  It is an iron-poor or iron-free
form of Epidote.

     Clinozoisite colors include: brown, pale green, greenish gray, pinkish-brown.

     The Monoclinic members share the atomic capacity to allow various partial cation
substitutions, for example, Aluminum in the zoisites, to Iron in Epidote, to Manganese and Iron
in Piemontite, to Manganese in Allanite.  Allanite fluoresces green under special ultraviolet lamps. 
Some radioactive isotopes can take place as well, such as Thorium, Cerium, and Lanthanum.  
Allanite lays atomic claim to the most abundant rare earth element, Cerium.

     With a relative hardness of 6.5, it makes for a settable gemstone, just a bit softer than
quartz (7.0).

     Today’s popular blue gemstone, Tanzanite, is a variety of Zoisite, found mainly in Tanzania,
Africa.   It contains chromium and strontium.  Tiffany & Company in New York popularized it in
1967.  Some hale it as a replacement for Sapphire.  Paradoxically, Anyolite, another variety, is
a green rock with some hornblende and actual corundum rubies.

Crystals

Clinozoisite Crystal, View #1 (Monoclinic)		Clinozoisite Crystal, View #2 (Monoclinic)		Zoisite Crystal (Orthorhombic)
Drawings by Ken Casey ©2005

Geology

     Clinozoisite forms primarily in regional and contact metamorphic rocks, and frequently
hydrothermal alterations of calcic plagioclase feldspars.   A process called "saussuritization”
exemplifies this group.  It was originally found at Sausalpe in the Austrian Alps.

     Locally, all members of the group, save Zoisite, have been found around the Franklin-Sterling
Hill, New Jersey ore-body.  Maryland and Pennsylvania both host Epidote and Clinozoisite.  Our
club has found some greenish Epidote crystals in Arundel Quarry in Havre de Grace, Maryland.

     Regionally, Clinozoisite can be found in small, but prolific crystals in the New England states.  
In North Carolina, particularly at the Spruce Hill Mine, it can be found in a rare igneous pegmatite.

     Amphibole (Nephrite) Jade can contain clinozoisite and/or zoisite, like the variety found in
Wyoming.  The interlocked crystal fibers contribute to its hardness of 6-6.5, and possibly the
green color.[iv]

     An interesting paper presented by Ferry in 1982, called “Phase Equilibria in Low Alumina and
High Alumina Pelites”, discusses that, with increased alumina introduced during paragenesis,
clinozoisite-out is but one of many reactions.[v]

     Perhaps the aluminum involved at the right temperature and pressure underwrites the creation
of corundum ruby in Anyolite, this author speculates.  You may wish to research this more on
your own.  I am so fascinated that I am.

     There is a lot more to the geology and chemistry of the Epidote Group.  There are at least
eleven other members in the group. I will leave you to study up on them during our break.  The
following links should be helpful:

http://webmineral.com/data/Clinozoisite.shtml

http://www.cs.cmu.edu/~adg/adg-psssimages.html#clinoz

http://ruby.colorado.edu/~smyth/min/epidote.html

		(Left & Top): Clinozoisite Crystals from the Chester Emery Mines, Chester, Hampshire County, Massachussetts Photomicrographs by & Courtesy of Scott Whittemore   ©2005

Locales

     Clinozoisite occurs around the world.  Many of the famous locales to date have been in
Europe, Asia, Africa, and North America.  According Jolyon Ralph’s continually updated
database at www.mindat.org, there are 360 global locations.[vi]

     A few well-cited places are: Austria, Switzerland, Italy (gemmy), Canada, Mexico,
United States (VT, ME, MA, CT, NH, PA, MD), Pakistan (gemmy), and Norway.

     Here is a list of mindat.org locale links in the United States:

Hunting Hill quarry (Rockville Crushed Stone Quarry; Travilah Quarry; Rockville Quarry;
Bardon Stone Quarry), Rockville, Montgomery Co., Maryland, USA

Keystone Trap Rock Quarry, Cornog, Chester Co., Pennsylvania, USA

Joppa Hill, Amherst, Hillsborough Co., New Hampshire, USA

West Redding grossular locality, Redding, Fairfield Co., Connecticut, USA

Goodall & Webster prospects (Sanford vesuvianite locality; Goodall Farm prospect;
Webster vesuvianite prospect), Sanford, York Co., Maine, USA

Chester Emery Mines, Chester, Hampshire Co., Massachusetts, USA

Mt Belvidere Mines (Vermont Asbestos Company Mines; Vermont Asbestos Group Mines;
Rubberoid Asbestos Mines), Lowell & Eden Mills, Lamoille & Orleans Cos., Vermont, USA

     Locations in Baja and Sonora, Mexico have produced bright pink radial, prismatic crystal
clusters, as well as brown, facetable crystals.[vii]

Clinozoisite Crystal Cluster (Locale unknown)			Zoisite Crystals (Locale unknown)
Photo by Stan Celestian © 2005 Glendale Community College, Glendale, Arizona		Specimens provided by the Arizona Mining and Mineral Museum, Susan Celestian, Curator

Uses

     We now know of three uses for clinozoisite; two are technological (and patented), and
one is more in the collector’s realm—as either a specimen or cut gemstone.

     We will first visit the technological uses.  To aid in fossil fuel refining, a carbon dioxide
fixing substance is employed.  Clinozoisite is a candidate for this process:

     U. S. Patent Application 20040163312, submitted August 26, 2004, by Inventors David P.
Bloomfield and James F. Stevens of Chevron Texaco, illustrates a process for diesel steam
reforming with CO₂ fixing.  A related process, used in the petrochemical industry, extracts
hydrogen from sulfur-rich hydrocarbons fuels, like diesel.  The Clinozoisite acts as
carbon-dioxide fixing substance in the catalytic reaction to make the hydrogen-rich
reformate.[ix]

     One benefit is the production of hydrogen gas for use in non-polluting fuel cells for cars,
trucks, and other vehicles.

     Our second use takes place in the improvement of the manufacture of textiles. 
Protective garments are made from materials that are resistant to environmental conditions
harmful to people, such as around venting volcanic gases, or accidental contact with cutting
tool edges.  To derive the benefit of increased protection, the fabric created must possess a
strengthening agent to meet the challenge of providing increased cut-resistance.  We will use
protective gloves as our example.

     According to United States Patent 6080474: “Polymeric articles having improved
cut-resistance”:

     Our third use is the most fun for mineral collectors and connoisseurs of fine gems. 
Yes, Clinozoisite can be cut and faceted from gemmy rough.  It can make a very pleasing
greenish to yellowish-brown cut stone.

     It’s closely related variety, Zoisite, has been worn in jewelry since at least 1967.  This
stone would be blue Tanzanite.  Another variety, Anyolite, combines contrasting green
calc-silicate with ruby red corundum.  Some great pictures of Anyolite jewelry can be found
at: http://www.jegem.com/1/singleProduct.aspx?SKU=AJR206890&r=redirected_from_ASP.

     A Manganese-bearing variety, called Thulite, has been named the official mineral of Norway,
where it occurs as pinkish-orange crystals.  It is sometimes used as an ornamental stone.

     Now that we have covered the science and uses of our MOTM, we are ready to go
collecting.  Let’s go!

Lapidary

Anyolite close-up		Norwegian Thulite Sampler		Faceted Tanzanite

     Many of the members of the Epidote Group take a polish well, especially Clinozoisite and
Zoisite.  Of the zoisites mentioned earlier, Thulite, Tanzanite, and Anyolite are the most used.

     I bet that Thulite (also called Rosaline) adorns many a Norwegian building, though I have not
evidenced this fact.  Perhaps you will want do an architectural study on your own.

     Of course, Tanzanite may be found all over the television home shopping channels.  I have
seen it mostly at www.jewelrytelevision.com.   A find on a visit to Tiffany's would also be a surety.

     I have not seen the green and red Anyolite in jewelry stores, but have passed it once at a
rock and mineral show.  A rare Tanzanian stone, it is prized metaphysically as an enhancer of
awareness and mental ability.  It also is purported to promote psychic empowerment.   As an
experiment, why not procure a piece, and try it for yourself.  You might even be able to foresee
what our selection will be for our next Mineral-of-the-Month!  Good luck!

Links

Glendale Community College Earth Science Image Archive

http://www.this-is-great.com/info/xbfffbjxnfxus

Until Next Time

     I hope you have enjoyed our uses revealed of this amazing stone called Clinozoisite.  It can protect
us from environmental pollution, though indirectly, and directly as incorporated into polymer fabrics that
are cut-resistant, and keep us safe.

     As a gem, it surpasses general impressions of glitz to those 'in the know'.  For the lapidary, it can
be a newfound, or old, friend.

    
     Until then, stay safe, and happy collecting.

Article Contributors

Scott Whittemore, Mineral Photomicrographer
Scott Whittemore’s Mineral Photomicrograph site

Stan Celestian, Glendale Community College, Glendale, Arizona

Susan Celestian, Curator, Arizona Mining and Mineral Museum

Jolyon Ralph, Mindat.org

Photo & Graphics Credits

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

Scott Whittemore, Mineral Photomicrographer
Scott Whittemore’s Mineral Photomicrograph site

Stan Celestian, Glendale Community College, Glendale, Arizona

Susan Celestian, Curator, Arizona Mining and Mineral Museum

Jolyon Ralph, Mindat.org