April 2018^ DISCOVER^35FROM TOP: EKLER/SHUTTERSTOCK; COLDMOON PHOTOPROJECT/SHUTTERSTOCK; VVOE/SHUTTERSTOCK
KEY SITES
Humans have collected and used ochre
since the dawn of our species, including
at these key archaeological sites:
Olorgesailie, Kenya: Researchers recently
discovered two pieces of ochre, intentionally
shaped by humans, that were at least 307,000 years
old. It’s the oldest such confidently dated find.
Blombos Cave, South Africa: Dated to
about 100,000 years ago, ochre-processing
“tool kits” and other artifacts found at the site —
including an engraved piece of ochre, the oldest
known art of its type — suggest early humans were
capable of modern, complex behaviors much earlier
than once thought.
Northern Cape, South Africa: Ochre
fragments from a cluster of sites suggest the
material was being collected as early as 500,000 years
ago, though some researchers dispute the dates.
Twin Rivers, Zambia: Pieces of ochre up to
266,000 years old include a quartzite cobble
stained with ochre that may be the earliest known
ochre-processing tool.
Porc-Epic, Ethiopia: The largest collection
of ochre pieces ever found, weighing nearly
90 pounds in total, includes a variety of tools to
process and use the material 40,000 years ago.
Maastricht-Belvédère, the Netherlands:
Fragments of ochre up to 250,000 years
old, found among animal bones and stone
artifacts, are the oldest evidence of the pigment’s
use by Neanderthals.
Rose Cottage Cave, South Africa: Researchers
have pieced together a story of ochre collection
and processing that spans more than 60,000 years,
from 30,000 to 96,000 years ago.Madjedbebe, Australia: Various ochre pieces,
found among thousands of stone tools, helped
researchers establish in 2017 that humans were in
Australia 65,000 years ago — 20,000 years earlier
than researchers thought.ROCK OF AGES
“Ochre is not one thing,” says archaeological
scientist Andrew Zipkin of the University of
Illinois at Urbana-Champaign. “That’s one of
the most annoying things about studying it.”
Ochre is most commonly defined by
archaeologists as any iron-rich rock that can be
used as a pigment. Most people associate the
term with hematite, or red ochre, chemically
known as Fe 2 O 3. But a range of other rocks
appear in the archaeological record, from the
yellow ochre goethite to the often-dramatic
specular hematite,
sometimes called specularite.
Zipkin contrasts working
with specular hematite — a
heavy, glittery rock that’s
deep purple-red and has a
high iron content — with
material much lighter in
both color and iron content
from Kenya’s volcanic
Rift Valley: “They’re both
ochre, but elementally
and chemically they are
radically different.”
To complicate matters even
more, when heated to at least
480 degrees Fahrenheit, yellow
ochre’s crystal structure changes
and the goethite can transform
into hematite, or red ochre.
Ochre use became widespread
in the Middle Stone Age, a
period of about 50,000 to
280,000 years ago, and during
this time, Hodgskiss says,
“there seems to be a preference for red — a larger
percentage of the ochre used was red. But a lot
of these sites have hearths one atop another. It’s
possible some of the red ochre we find may have
been yellow once.”SEEING RED
Confidently dated archaeological sites showing
ochre worked by humans now go back more
than 300,000 years, close to the emergence of
Homo sapiens. And we’re not alone in the use
of ochre. Numerous sites in Europe and western
Asia show that our closest evolutionary kin, the
Neanderthals, also used ochre beginning at least
250,000 years ago, although their applications
of the material appear much more limited.
Intentional ochre collection and use, however,
may have begun much earlier in our family tree.
“I wouldn’t be surprised in the least if theGoethiteHematite