How Does Hematite Work?

Hematite is a mineral that we've been using for pigments, as a source of iron, and in other applications for pretty much ever. Learn how it works in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/environmental/earth/geology/hematite.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeart Radio, Hey brain
Stuff Lorn Vogel bomb here. The mineral hematite has shaped
civilizations for thousands of years. It was first used as
the main pigment in cave paintings, often having a reddish hue,
a signature trait of hematite. Later, it was and still

(00:23):
is the primary source of iron, shifting the world out
of the Stone Age and into the Iron Age and beyond.
While heemotite comes in many different shapes, sizes, colors, and forms,
it always streaks red, garnering its name, which is based
on a Greek root for blood and the nickname Bloodstone.

(00:45):
Haematite can appear steel, gray, black, brown, or red, and
can shine in the form of metallic crystals or show
up as dull, reddish rough rocks. And hematite isn't exclusive
to Earth. It's the main reason that the planet Mars
is red. Roughly ten to fift of its soil is
made up of the mineral. Fine grained hematite is dispersed

(01:05):
around Mars during its many seasonal dust storms. In its
base form, hematite is an iron oxide composed of iron
and oxygen. As one of the most abundant minerals on
the planet Earth. It's perfect for mining to produce iron
and iron based derivatives like steel. But even though it's plentiful,
hematite isn't usually found on Earth on its own, or

(01:28):
rather it's generally found mixed together with other minerals like magnetite.
For the article, this episode is based on How's to
Fork spoke by email with Brad le Blanc, senior geoscientist
for Sweet Lake Land and Oil and Oil Refinery in Louisiana.
He explained that hematite quote forms as a reaction of
hot magmas with surrounding materials and likely eroded into concentrated

(01:53):
layers of down dip sedimentary beds, the separating out via
gravity distribution. He Atite can also precipitate out of lake waters,
forming a bed on lake bottoms. As hematite can be
formed in different ways, it can have different physical traits.
This can make it rather hard to identify based on

(02:13):
just appearance alone. Intuitively, it's not easy to think that
a rainbow metallic crystal is actually the same kind of
mineral as a rough black specimen, but these are both
forms of hematite. The mineral does have that big tell
though regardless of how it looks due to its high
iron and oxygen content, But when it's scratched against anything,

(02:35):
it always leaves a reddish brown powder. So how did
our planet wind up with so much hematite? Back when
Earth was covered in primordial oceans about two and a
half billion years ago, there was an abundance of iron
in the water. When early aquatic plant life that could
process sunlight and undergo photosynthesis started forming, the oceans began

(02:59):
filling with oxygen. In this oxygen bound with the iron
in the water, forming rust particles. Over time, these sank
to the bottom of the ocean's floor, compressing into banded
iron deposits, which are the primary source of hematite today.
This accumulation continued for hundreds of millions of years. Along

(03:19):
with hematite, in these sedimentary iron deposits, there's also magnetite,
another primary source of iron. The mixing of these two
minerals in different quantities is one of the ways hematite
can take on different forms. While hematite is mainly mined
for iron, there are several other uses for the mineral
going back to the earliest civilizations. As we briefly discussed above,

(03:42):
hematite is one of the main ingredients of red ochre
pigment used for paints, makeup glazes, and early cave drawings
in Paleolithic eras a red ochre was also used in
paintings of the Renaissance era. Since hematite can present itself
in crystalline forms, it's also used and jewelry. When polished
or tumbled, the mineral can give off a smooth, metallic appearance,

(04:05):
making it perfect for beads of all shapes and sizes.
The mineral has also been used as a healing stone,
sometimes said to bring relief from medical problems like anemia,
leg cramps, and insomnia, though there's no scientific proof of
any of that. But there is a real medical use
for hemotite. It can stop X rays and so is
used in radiation shielding for medical equipment. But these other

(04:29):
uses of hematite don't make up a significant portion of
the mineral's use overall, not when compared with iron production.
While hemotite can be found virtually everywhere in the world,
large quantities of it are mined in places like China, Brazil, Venezuela, Australia,
and South Africa, as well as across the US in Canada.
Some of those mines removed more than a hundred million

(04:51):
tons of iron ore every year, including hemotite, magnetite, and
other products m Today's episode is based on the article humatite,
the shapeshifting mineral used from the Stone Age to today
on how stuff works dot Com, written by Trevor English.
Brain Stuff is production of I Heart Radio in partnership

(05:13):
with how stuff Works dot Com, and it is produced
by Tyler Clang. Four more podcasts from my heart Radio,
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