Red Agate Vs. Carnelian

What is the difference between red agate and carnelian? Can someone
help me answer this question?


Actually, red agate is carnelian and is chalcedony, and is
chrysoprase, and is agate, and is plasma and is sard (though sard is
normaly thought of as being more opaque and more less orange). If you
goggle it and look at some of the mineral sites you would be amazed
at the confusion.

Kind of like today the confusion over the yellow/green/opaque
chrysoprase we normally think of as from Australia is now, for some
unknown reason, being advertised as magnasite (aka magnesite) the
latter being a carbonate (calcite) and nothing even near the silca
family. And in fact, you won’t even see magnasite listed on a mineral
site - anywhere

hi -

this is comparing agate and carnelian finished pieces: cabochons,
beads, tongues, etc. getting into the ‘rough’ or massive examples of
each gets into a lot more detail than needed here.

first, red agate can be a true, clear red in color, but is seldom
without some pattern: bands - bubbles - zigzags - that include
colors. the red parts are seldom translucent.

on the other hand, carnelian is not a true red. carnelian can be
burnt orange, brownish orange, ‘zones’ of brownish orange with burnt
orange, some pale burnt orange, some pale brownish orange - you get
the picture of the color varieties some carnelian can be solid and
uniform in color, some have white or clear bands running through the
burnt orange, brownish etc. etc.


Dawn, there is basically one difference, the red agate is heat
stabilized to produce a clearer, darker stronger red than in typical
banded red agate; that is then carnelian. Carnelian is the
antiquarian term for heated red agate favored in the Roman empire for
the deep colour and the attached, purported, mystical properties -
all relics from pre-christian tradition(s). Carnelian also denotes a
slightly higher quality agate (no banding) was chosen to heat…


Assuming that the stone has not been dyed, carnelian is the
traditional name used to describe the red to reddish brown variety
of cryptocrystalline quartz (agate). While there IS an
internationally recognized procedure for the naming of MINERALS, no
such thing exists for variety names of gem and near-gem and lapidary
material, much of which is rock and not mineral. This seems to cause
quite a bit of confusion among people who are not directly involved
in lapidary, but just be aware that one man’s red agate could be
another man’s carnelian.

Many times, the reddish component of carnelian, sard, sardonyx,
brownish red agate, reddish brown agate, whatever you wish to call
it, can be intensified by heating, which alters the iron causing the
coloration. At one time, the predominant source of fine carnelian was
actually the United States! Even today, one can find excellent
material along the banks of Newaukum Creek in WA state (and
elsewhere, see Sinkankas’ Gemstones of North America), where it
weathers out of the soil banks. Private property, ask for permission
first. August-Sept best time for the hunt. (It’s a bit of a hike).

And if it’s red like the red in the flag, it’s dyed. Of course, it
cold be a beautiful brownish red and still be dyed, too. Usually,
there is no quick and easy way to tell, it’s often a matter of
having handled a lot of material, but that’s no guarantee, either.

If you have a concern for owning/using an un-dyed piece, you could
work directly with a lapidary shop and have the material cut without
any intervening treatment. And they won’t know and can’t tell if it
has been heat treated after “mining” unless they dug it out of the
ground themselves.

Carnelian (also commonly called sard or sardonyx) has a long history
in cultures around the world. Many fine examples exist in
Mesopotamian and Egyptian jewelry and it was commonly used for seals
in Roman times. Aaron’s breastplate, etc…

Wayne Emery
The Gemcutter

Carnelian is also often (maybe usually) heated.