Dear Dave,
The process you described is fascinating! I’ve never heard of this
before. I have no idea why one type of volcanic glass would react this
way but not another. Maybe someone else out there does.
By the way, do Apache Tears from other locations also turn into these
"snowballs" when heated? If not, maybe it’s something in the Arizona
environment.
Beth
Beth;
I believe that the whole solution to this mysterious stone is that it
is formed in a by- product called perlite- It is a compacted,
grayish-white powdery type of material–the principle mined material,
I think for use as a fire retardant… I’ve tried to contact rock
hounds/shops in Mesa, Arizona–but nothing back from them, yet To my
knowledge, this is the only outcropping of this particular stone. Do
enjoy—
Dave
(Seattle)
Dave wrote:
. . . I’ve tried to contact rock
hounds/shops in Mesa, Arizona–but nothing back from them, yet To my
knowledge, this is the only outcropping of this particular stone.
According to Pough (Field Guide to Rocks and Minerals), obsidian is
only found where volcanic activity has taken place in relatively
recent (geologic) times, for with time it tends either to crystallize
into a fine-grained rock or to decompose by taking on moisture. Old
obsidian flows may take up water and change from a glassy luster to a
duller gleam.
It is this moisture in the altered rock which makes it swell up when
heated, turning it into a sort of artificial pumice. The man-made
form is sold as artificial “perlite”.
Natural pumice forms when a gas-filled mass of lava is hurled from a
volcano and the gas bubbles expand within the lava before it freezes,
making a light glassy froth.
“Apache tears” form when cracks develop in the obsidian. Moisture
causes the alteration along the network of cracks, leaving a series of
rounded, glassy nodules in a natural perlite.
The western US volcanic belt and obsidian formations extend into
Mexico.
HTH
Pam Chott
Song of the Phoenix
FYI,
There is a place in New Mexico about half way between Albuquerque and
Santa Fe, just west of the Chochiti pueblo called Tent Rocks. It has
been in many old western movies due to the unusual rock formations.
If you walk around these formations and up and down the ravines you
can Apache tears every where you go. most are about 10mm in diameter
but you can also find a few as large as 25-30mm. Most are either
gray, or brown but you can also find many that are greenish brown to
green. They all look like they have been tumbled and are nice and
shiny.
Phillip Scott GG
All,
I live in Apache Tear country, Arizona. There are at least five
different locations in Arizona alone where you can find Apache Tears.
I have the normal tears in black or brown color, banded tears in
black color, and a few yellow and green/yellow tears that are
faceable. Tears can be bought at most of the local rock shows. All
the local locations are in the Rockhound Guide Books for Arizona. At
least three of the locations are on public land. Come see us at the
Scottish Rites Center in Tucson from Jan 29-Feb 11, 2001. We have
95% stones cut by us. Concaved faceted stones are our specialty.
Along with normal facetted stones and a lot of cabochons.
Looking Foreword to seeing you,
Gerry Galarneau
Galarneau’s Gems
www.galarneausgems.com
Rather then heat them to 2,000C to make inexpensive insulation
material,you should try heating them to 650F(forgive me for using
Fahrenheit rather than Centigrade throughout).The reason I use F is
the heating must be done in an oven where you can see what is
happening.I use a convection(for the even flow of air across the
stones to reduce breakage) toaster oven set to broil(500F)but you
leave it on for 1-3 hours or more,the rate of rise brings it up to
650F.Irradiated Quartz will come back from the lab an opaque
black.You then heat it,and can produce any number of colors of
Citrines,even Amethyst.Some natural Smoky Quartz will also turn to
Citrine when heated like this.I have never tried Apache Tears,it is
an obsidian,not a quartz.But seems to me the smoky color was induced
by irradiation in nature and a lower heating temperature might give
you some dramatic new color.You must sit in front of the glass door
to watch as the color change on some of the quartz is fast.You have
to observe,and just as it is changing,quickly open the door and
snatch them out.Further,you should try heating temperatures lower and
higher than what I have recommended for Quartz.When it goes clear you
will know you have overheated or there is no chance for a color
change prior.Also,it might be advantageous to irradiate them
prior,then try the heating process.Natural irradiation is often
weak,a higher laboratory dose might induce the color center.The
dosage on Quartz ranges from 50 megarads on Colbolt 60,to 500
megarads.Some Quartz the higher the dose induces different colors.If
anyone has success,remember to send to me my consulting fee.For
sure,not even 1/100 of 1 percent of all the world’s Quartz has been
tested.Think about all the variables,it could take 100 lifetimes.But
I have made from near worthless clear Quartz,dark Orange,a
Red-Orange,all sorts of Lemon,Yellows and Goldens.I have even made
Emerald Green and a Strawberry Red color.At this URL I have a paper
describing some of my experiments in this area,which I am adding a
new one to right now.
http://www.LICCINI.com/Treating/Quartz/Quartz.htm Also,I will be
publishing the complete treatise of the real inventor of this
process,the U.S.Government in the late 40’s and 50’s hoping to find
some war device out of it.Any professional reading this,who is
interested to be a collaborator on this work,contact me please.The
laboratories have minimums,8kilos to hundreds,one needs multi-ton
lots to be practical.Therefore a marketing problem for the volumes
needed just to run a test. Mark Liccini http://www.LICCINI.com