Jaspers with Orbs How to Guide
I don’t know
anyone who doesn’t enjoy looking at the amazing orb jaspers, the patterns of
orbs, with the shapes of oval, round, egg as found in the “porcelain jaspers”
are rare and favorites of collectors. Yet there is mystery on how these orb
type jaspers were formed. There is a wonderful book by Marco Campo-Venuti,
Genesis and Classification of Agates and Jaspers; a New Theory (Tipografia
Luciani, Rome,2012) That the author presents a in depth discussion of jaspers
and the major types, classified into four groups: Ocean Jaspers, Volcanic
Jaspers, Jaspers Paedomorphic on Fossils, and Chemicals Jaspers. Orb Brecciated
and Jasper-Agates.
History
The name Jasper means "spotted or
speckled stone" coming from Hebrew and likely Greek definition and
possible even Persian. In Israel the first stone on the High Priest's
breastplate, was a red jasper, whilst Tarshish, the tenth stone,
this dates to 1300 BCE. We know that Jasper occur in Fossils showing that they
continue to form though history. On Minoa Crete, jasper
was carved to produce seals circa 1800 BC, as evidenced by archaeological
recoveries at the palace of Knossos.
Orb Jasper
Properties
A very basic
description is that the Chemical Jasper classification, that includes our
beloved orb jasper is a s follows; preexisting cavities in the rock filled with
deposits from colloidal silica that flow into these cavities and is described
as a very complex process. Regardless the process results in nodules and veins
of the orb type jaspers. The orbs are formed by contrasting materials/chemicals
the create a kind of water in oil phenomenon this is what basically forms our
orbs under pressure heat and varied chemicals we get the variety of orb jaspers
we all enjoy so much. The sited book above you can read in depth of the 3
stages that make this possible. Or if you prefer a shorter version see (“Rock & Gem” magazine Vol 49 issue June 2019 pg.
52-56 by Joe Dehmer, Understanding ORB structure in Jaspers, part 1).
Jasper is an aggregate of microgranular quartz and/or chalcedony and
other mineral phases, is an opaque impure variety of silica usually
red, yellow, brown or green in color; and rarely blue. The common red color is
due to iron
inclusions. The fracture is usually smooth. The specific gravity of
jasper is typically 2.5 to 2.9. Hardness: 7. Stone Type/Family: Member of the Chalcedony
Clan. Crystal System: Trigonal. Chemical
Composition: (SiO2) Silicon Dioxide with inclusions (iron hydrates)
Color: Most commonly a tan to beige colored stone containing "spots" or “orbs” and/or bands of darker colors (red, pink, black, brown, gray, and/or olive green) which look somewhat like the spots found on a Leopard.
Color: Most commonly a tan to beige colored stone containing "spots" or “orbs” and/or bands of darker colors (red, pink, black, brown, gray, and/or olive green) which look somewhat like the spots found on a Leopard.
Popular
Variety’s
Ocean
Jasper. The trade name ocean jasper is used for
a variety found along coast of northeast Madagascar. In Nebraska orbicular
jasper is found in altered rhyolite beds noted for a variety of jaspers and
related agates. https://www.entertheearth.com/the-geology-varieties-and-history-of-ocean-jasper-part-one/
Poppy
Jasper. Morgan
Hill Poppy-patterned
jasper or Poppy jasper is famous and very rare, with red to orange orbs with red
and yellow dots that appear as poppy flowers. The material is at Morgan Hill,
Santa Clara County, California.
Mexican Red. A red to very dark chocolate
red and bwown.
Washington Red. These usually small stones
can be found in quite a few places throughout Washington. The jasper can
be found further inland as well. Many of the rivers and creeks on the Olympic
Peninsula contain nice samples of orbicular jasper, and larger pieces can be
found too. Generally, you will find bigger pieces of material further upriver
as you get closer to the source.
Nebraska. In Nebraska, orbicular
jasper is found in altered rhyolite beds noted for a variety of jaspers and
related agates. Its colors are more earthy tones of grays, deep reds, and
pops of coppery orange in these stones.
Collecting; Be
aware many areas are closed off or depleted as this is hard to find material. Polka
dot Mine. Madras, Oregon and they are open to
visits. contacts Dennis English, Still Rand, or Westcoast Mining at info@wcmining.com, 509-522-4851 or
541-901-1445. https://www.oakrocks.net/blog/polka-dot-agate-mine/
Washington
red poppy jaspers Most commonly they are found on beaches of
the Pacific Ocean on the Olympic Peninsula. They are generally more plentiful
along the north coast, but they have been found further south as well. Rialto
Beach is a another collecting site. Good specimens have been found at Damon Point just south of Ocean Shores, Washington. Other good
areas include beaches around Port Angeles and Port Orford.
Lapidary;
Cutting large rocks of Orb
jasper can be done best with oil lubricating your saw as this material is quite
hard. Smaller trims of your slabs can be done with water cooled blade cutting. You
will start with a 100-grit wheel to shape your stone working down to 200 then
400 then 600 grits as you see fit, then polish with most polishing compounds
will work. Do look out for cracks that could ruin your material, and fill with
a crack repair epoxy if desired before cutting and shaping your cabochon. (Please
see our blogs on “Lapidary saws” and “Lapidary Grinding”.
Join me on the
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References
See (“Rock
& Gem” magazine Vol 49 issue June 2019 pg. 52-56 by Joe Dehmer,
Understanding ORB structure in Jaspers, part 1)
Marco Campo-Venuti, Genesis and Classification
of Agates and Jaspers; a New Theory (Tipografia Luciani, Rome,2012)
"U.S. Geological Survey,
Chalcedony Site". www.USGS.gov.
Jump
up to: a b Kostov, R. I. 2010. Review on the
mineralogical systematics of jasper and related rocks. – Archaeometry Workshop,
7, 3, 209-213. PDF
Hanks, Patrick; Hardcastle, Kate; Hodges, Flavia
(2006). A Dictionary of First Names (2 ed.). Oxford University Press.
p. 138. ISBN 978-0198610601. Jasper: The usual English form of the name assigned in
Christian folklore to one of the three Magi or 'wise men', who brought gifts to
the infant Christ at his birth (Matthew 2:1). The name does not appear in the
Bible, and is first found in medieval tradition. It seems to be ultimately of
Persian origin, from a word meaning 'treasurer'. There is probably no
connection with the English vocabulary word jasper denoting a
gemstone, which is of Semitic origin.
Kulke, Hermann; Rothermund, Dietmar (2004). A
History of India. Routledge. p. 22. ISBN 0-415-32920-5.
One or more of the preceding
sentences incorporates text from a publication now in the public domain: Frederick William Rudler (1911).
"Jasper". In Chisholm, Hugh (ed.). Encyclopædia Britannica (11th ed.). Cambridge University Press.
Hastings's Dict. Bible, 1902, as cited in 1911 Britannica.
Broecker, W.S. (1985). How to Build a
Habitable Planet.
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