Iris (Rainbow) Agates
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Item# HMIA0509001
Polished Horse Mountain
Iris Agate
$75.00
Quantity Available 1 each

Iris agate owes its spectral colors to the presence of a diffraction grating structure. The iris agate grating structure results
from the segregation of alternate layers having higher and lower refractive indexes during crystallization of the needles or
fibers of chalcedony.

Iris is observed in highly polished and thin cut agate (about 1.5mm or 1/16th inch) up to about 6mm or 1/4 inch. The iris is
observed by placing the specimen in front of a light source at about arms length and moving the specimen until the light
passing through the specimen reveals the spectral colors. It must be viewed at the correct angle to see the Iris effect.

"A specimen which shows primary colors in very thin section may show only pastel colors if it is cut too thick. If the line
spacing is not quite uniform only pastel colors may be seen, and if it is very irregular only a chatoyance will be observed."
The conditions for Iris to occur are quite specific. When the conditions are close but not good enough then the occurrence
is chatoyance and not Iris. Simply put, If there is not a play of color, it is not Iris.
                              (quotes from American Mineralogist Vol 37 pages 578-587, published in 1952)
HORSE MOUNTAIN IRIS AGATE...ONE OF AMERICAS FINEST HIGH GRADE IRIS AGATES
          
  This material is from closed sites in middle Tennessee and while relatively unknown today to all but some old time rock
hounds, this is some of the  WORLDS  BEST. There are two basic types of Iris from Horse Mountain and the first is the
clear to whiteish material common to all iris sites. The second is unique for U.S. material as far as we know and has a
brown body color to the agate. Other sites may have blobs of color or dendrites but not the brown body color.   Mentioned
in Judith Zeitners   " APPALACHIAN MINERAL & GEM TRAILS "   in 1968  this material has been depleted long ago.

  This stone is backlit with a 40w incandescent bulb for pictures and the camera is a Nikon D40X using an 18-55 Nikon
lens and usually used with a Mercury Optics 52mm 0.45x macro lens. While viewing these pictures (taken by Rockman 836
Lapidary) please remember that the camera shows greater detail of the stone than is generally visible with the naked eye.
Please note; although we are lucky enough to have a few pieces of Horse Mountain Iris Agate to sell …do not think that
this is common material…it is not. When this stock is gone there is no more available.
  This stone is 2.25 x 1.15 x .1" (57 x 29 x 3mm) in size and weighs 9g. We have pictured the flaws in this stone. There are
2 natural cracks in it as you can see. The stone is structurally sound and has been cut, ground and polished. This stone is
prettier than the pictures show and is top multicolor vivid level iris for over 40% of the stone. This specimen is a VERY fine
brown iris agate and a great example of why the best Horse Mountain Iris Agate rivals or beats the best from anywhere in
the world.
HORSE MOUNTAIN IRIS AGATE...ONE OF AMERICAS FINEST HIGH GRADE IRIS AGATES
        
This material is from closed sites in middle Tennessee and while relatively unknown today to all but some old time rock
hounds, this is some of the  WORLDS  BEST. There are two basic types of Iris from Horse Mountain and the first is the
clear to whiteish material common to all iris sites. The second is unique for U.S. material as far as we know and has a
brown body color to the agate. Other sites may have blobs of color or dendrites but not the brown body color.   Mentioned
in Judith Zeitners   " APPALACHIAN MINERAL & GEM TRAILS "   in 1968  this material has been depleted long ago.
This stone is backlit with a 40w incandescent bulb for pictures and the camera is a Nikon D40X using an 18-55 Nikon lens
and usually used with a Mercury Optics 52mm 0.45x macro lens. While viewing these pictures (taken by Rockman 836
Lapidary) please remember that the camera shows greater detail of the stone than is generally visible with the naked eye.

Please note; although we are lucky enough to have a few pieces of Horse Mountain Iris Agate to sell …do not think that
this is common material…it is not. When this stock is gone there is no more available.

This stone is 1.875" x 1.25" x .09" in size. The band of upper bright lower vivid band of iris is 7/16 " wide and curves arond
the center of the stone. The body color where the iris is is a very light transparent brown and not the translucent milky
white material you commonly see. The primary colors of this stone are in the green, red, orange and blue areas. This is a  
nice fortification pattern stone and an interesting speciman from a closed area.
Item# HMIA02103875
Polished Horse Mountain
Iris Agate
$69.00
Quantity Available 1 each
Item# HMIA0509003
Polished Horse Mountain
Iris Agate
$60.00
Quantity Available 1 each
HORSE MOUNTAIN IRIS AGATE...ONE OF AMERICAS FINEST HIGH GRADE IRIS AGATES
      
This material is from closed sites in middle Tennessee and while relatively unknown today to all but some old time rock
hounds, this is some of the  WORLDS  BEST. There are two basic types of Iris from Horse Mountain and the first is the
clear to whiteish material common to all iris sites. The second is unique for U.S. material as far as we know and has a
brown body color to the agate. Other sites may have blobs of color or dendrites but not the brown body color.   Mentioned
in Judith Zeitners   " APPALACHIAN MINERAL & GEM TRAILS "   in 1968  this material has been depleted long ago.

This stone is backlit with a 40w incandescent bulb for pictures and the camera is a Nikon D40X using an 18-55 Nikon lens
and usually used with a Mercury Optics 52mm 0.45x macro lens. While viewing these pictures (taken by Rockman 836
Lapidary) please remember that the camera shows greater detail of the stone than is generally visible with the naked eye.
Please note; although we are lucky enough to have a few pieces of Horse Mountain Iris Agate to sell …do not think that
this is common material…it is not. When this stock is gone there is no more available.
This stone is 1.1 x 0.9  x .1" (29 x 23 x 2mm) in size. The band of multicolor iris is about 75 percent of the stone. As you
can see most all of the colors of the best Horse mountain are there only missing the deep purples and teals. This is lower
vivid in iris level and is a fine specimen. This would make a very nice cab but this specimen is quite stunning as it is.
Notice:

The Horse
Mountain
Iris Agates
listed on
this page
are the very
last stock
we have
available
and since
the source
was
depleted
decades
ago we will
no longer
have any of
this
available in
the future.
We are
always
looking for
old stock
sources but
this mineral
appears to
be
unavailable
at any
reasonable
price.

The USA
Oregon Iris
Agate is still
available
but is not
nearly as
pronounced
or vibrant
as the Horse
Mountain
Iris Agates
HORSE MOUNTAIN IRIS AGATE...ONE OF AMERICAS FINEST HIGH GRADE IRIS AGATES
      
This material is from closed sites in middle Tennessee and while relatively unknown today to all but some old time rock
hounds, this is some of the  WORLDS  BEST. There are two basic types of Iris from Horse Mountain and the first is the
clear to whiteish material common to all iris sites. The second is unique for U.S. material as far as we know and has a
brown body color to the agate. Other sites may have blobs of color or dendrites but not the brown body color.   Mentioned
in Judith Zeitners   " APPALACHIAN MINERAL & GEM TRAILS "   in 1968  this material has been depleted long ago.
This stone is backlit with a 40w incandescent bulb for pictures and the camera is a Nikon D40X using an 18-55 Nikon lens
and usually used with a Mercury Optics 52mm 0.45x macro lens. While viewing these pictures (taken by Rockman 836
Lapidary) please remember that the camera shows greater detail of the stone than is generally visible with the naked eye.

Please note; although we are lucky enough to have a few pieces of Horse Mountain Iris Agate to sell …do not think that
this is common material…it is not. When this stock is gone there is no more available.

This nearly water clear stone is 1.5" x 1.125" x .10" in size. The banding is .375" wide and 1.5" long and is what I would call
medium bright at best. The pictures show very well the extent and color of the iris.
Item# HMIA02102575
Polished Horse Mountain
Iris Agate
$52.00
Quantity Available 1 each