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Hematite has several
varieties, each with their own unique names.
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Hematite
Rose is a circular arrangment of bladed crystals giving the appearance
of the flower of a rose.
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Tiger
Iron is a sedimentary deposit approximately 2.2 billion years old
that consists of alternating layers of silver gray hematite and red
jasper, chert or even tiger eye quartz.
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Kidney
Ore is the massive botryoidal form and gives the appearance of lumpy
kidney-like masses.
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Oolitic
Hematite is a sedimentary formation that has a reddish brown color
and an earthy luster and is composed of small rounded grains.
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Specularite
is a micaceous or flaky stone that is sparkling silver gray and sometimes
used as an ornamental stone.
Hematite is an
important ore of iron and it's blood red color (in the powdered form)
lends itself well in use as a pigment. Hematite gets its name from a
greek word meaning blood-like because of the color of its powder. Ancient
superstition held that large deposits of hematite formed from battles
that were fought and the subsequent blood that flowed into the ground.
Crystals of Hematite are considered rare and are sought after by collectors
as are fine Kidney Ore specimens.
Pictured above is a rough Hematite in my collection that weighs approximately
6.5 lbs.
Here
is a sample of a pendant I created from Hematite using wire sculpture
and a 4.5 ct. Swiss Blue Topaz. The Hematite cabochon at the top is
18mm X 15mm:
A simple
test to determine if hematite is genuine is to take a piece of stone
and scratch along the bottom of a china plate. If the mark left is red-
it's genuine. Manmade hematite, often called Hematine will leave a gray
streak.
This
method of testing Hematite was gleaned from a geology professor at Occidental
College in California. I went to an expert on About.com (Thomas) to
inquire if he had ever heard of this method and whether or not he agreed
with it. Here is what Thomas had to say:
Jayne,
"Other
minerals may leave a red to reddish streak on porcelain surfaces. The
key to using such a test is to eliminate other minerals by other characteristics
such as appearance, surface luster, break edges, magnetic properties,
hardness, etc.
Hematite
does indeed leave a red streak on a porcelain streak plate. Some may
use the back of a china plate, others the back of a porcelain tile or
a purchased streak plate made for the purpose of field tests of minerals
streak color.
I
assume you will be able to eliminate plastics, etc., fairly easily without
a streak test.
The
fake hematite made from other minerals called Hematine should not leave
the red streak. Hematite does streak red.
The
porcelain streak will not work for minerals harder than the porcelain,
such as quartz, because the material will scratch the test plate surface.
If
stones are already set, it may be difficult to test without leaving
a spot on the stone. If you can get to an unseen area, by all means
use this streak test along with magnetism (hematite is not attracted
to a magnet and the Hematine sort of fake is attracted).
Jayne,
the professor makes a valid point. Go try it!"
God
Bless and Peace. Thomas. August 5, 2007 2:24pm
I used known samples to perform the test; Once
with the rough stone shown above and once with a finished piece sold
as manmade. The rough did produce the red streak, the manmade did produce
a gray streak. Though I didn't perform the test numerous times, (due
to the affect it may have had on my china) the technique did produce
the results expected.
PHYSICAL CHARACTERISTICS:
Color is steel or silver gray to black in some forms and red to brown
in earthy forms. Sometimes tarnished with irredescent colors when
in a hydrated form (called Turgite).
Luster is metallic or dull in earthy and oolitic forms.
Transparency: Crystals are opaque.
Crystal System is trigonal; bar 3 2/m
Crystal Habits include tabular crystals of varying thickness sometimes
twinned, micaceous (specular), botryoidal and massive. also earthy
or oolitic.
Cleavage is absent however there is a parting on two planes.
Fracture is uneven.
Hardness is 5 - 6
Specific Gravity is 5.3 (slightly above average for metallic minerals)
Streak is blood red to brownish red for earthy forms.
Associated Minerals include jasper (a variety of quartz) in banded
iron formations (BIF or Tiger Iron), dipyramidal quartz, rutile, and
pyrite among others.
Notable Occurrences especially nice specimens come from England, Mexico,
Brazil, Australia and the Lake Superior region.
Best Field Indicators are crystal habit, streak and hardness
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