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Working with Gypsum


#1

My aunt from Texas brought a big bag of gypsom for me to use and I
must admit, although grateful, I haven’t a clue what gypsom is, how
to polish it, etc. I’m new to this. Thanks!

Suzanna


#2

gypsum is very soft, very hard to cut/polish, not very useful for
jewelry; primary use is in the wallboard in housing.

john


#3

it is actually dangerous if inhaled- not something i would cut and
polish particularly if you aren’t going to wear a respirator !. We
use it to lighten plaster for investing (or repairing plaster
walls!). it is the stuff sheetrock is made of. and not usually used
in jewelry making as a cabochon. It is very soft and gives textured
ceilings and walls that sparkly appearance (like a construction
"glitter" it is sold as an additive for texture coatings too). rer


#4
it is actually dangerous if inhaled- not something i would cut and
polish particularly if you aren't going to wear a respirator !. We
use it to lighten plaster for investing 

It is plaster! Gypsum is calcium sulfate dihydrate, plaster or
plaster of paris is what results from heating gypsum to 150 C when
some of the chemical water is driven of resulting in calcium sulfate
hemihydrate which is called plaster. When you add water to it it
returns to gypsum! The mineral form may have other minerals in it
that could be hazardous but gypsum itself is not too hazardous but
breathing any fine dust is not a good idea.

James Binnion
James Binnion Metal Arts


#5

Gypsum is a mineral which comes in many different forms, clear
crystals (selenite), Massive (alabaster), spectacular needles of
various colors, and more. I don’t know what you have. It’s very soft.
If it’s selenite, it cleaves very easily, so the direction of polish
is important. It can be polished by carefully hand wiping on a wax
surface with alumina polish. Alabaster is sometimes “polished” with a
hand-rubbed coat of wax.

In general, gypsum is not a good lapidary or jewelry material.

Al Balmer
Sun City, AZ


#6

In my hometown of many years ago, there was a factory(closed a long
time now) that used gypsum to manufacture some kind of insulation
products. My father worked there as a young man, long before I was
even a twinkle in his eye. He now has dementia/alzheimers and we
cant get much out of him(he rarely speaks directly to me as we don’t
think he knows who I am anymore), so I am unable to ask him for any
additional info.

EdR


#7
It is plaster! Gypsum is calcium sulfate dihydrate, plaster or
plaster of paris is what results from heating gypsum 

Very true, but it creates fantastic crystals! The gigantic crystals
in Mexico’s much-ballyooed Crystal Cave are all gypsum crystals. See:

Inside the Crystal Palace

http://www.canyonsworldwide.com/crystals/mainframe3.html

Rick Martin
www.artcutgems.com


#8

Bummer…someone in your family thinks they’re contributing and you
don’t know what to do except say “Thanks” and let it collect dust.

Suzanna


#9

Breathe and death follows—that really is a fact. But death is NOT
a consequence of breathing!! (To be safe though, DON’T
BREATHE----then breathing will NOT be the cause of your death!
–Well, except, maybe, that you already did it?)

The flaw in the logic even has a technical name:
Whatever-follows-must-be-the-consequence Fallacy.

The bottom line is it takes far more than sequence to PROVE a real
cause. My mother died of dementia/Alzheimer’s and she NEVER worked in
a gypsum factory. (Or anything close. Only the last 10 or so years of
her 83 year life were even spent in a building with gypsum wallboard.
Ough-oh, I’ve lived the last 15 years in places with gypsum
wallboard…)

James E. White


#10

I have slabbed some blue and yellow selenite with the thought of
making a lampshade or two. It takes a fair finish with a buffing
wheel, Zam and a light hand. I have seen it sealed with epoxy also. I
have cut some thicker slabs for experimental casting medium. It
should work like cuttlefish…Bob


#11

Hey Bob,

I hope you are going to post pictures. Wear a mask!

Bobbie Horn


#12
It is plaster! Gypsum is calcium sulfate dihydrate, plaster or
plaster of paris is what results from heating gypsum 

Do you think I should use them? Any health hazards from using/
wrappring wire around it or wearing it?

Suzanna


#13

wire wrapping should be fine i would guess- but do wear a respirator
when cutting it, or forming, grinding etc. the small particles are
like needles in your respiratory tract despite what anyone may say
about the safety of the plaster form- which is far more processed
than what you have - you are not using the plaster form or
alabaster. selenite is what i’m betting you have and it’s gypsum-
gypsum being a hazaardous mineral (would you cut asbestos without a
respirator?) warrants appropriate PRE-CAUTIONS…so wearing the
crystals should be ok once polished and sealed…I’m wondering what
the hobbyist community that attaches metaphysical properties to
!minerals has to say about gypsum… probably a curative for
respiratory problems! (like cures like being the thought process
there… )


#14
gypsum being a hazaardous mineral 

Please provide any data on gypsum being a hazardous mineral. Yes
other minerals that might be in the same piece can certainly be
hazardous but gypsum it self is not.

James Binnion
James Binnion Metal Arts


#15
gypsum being a hazaardous mineral 

No RER. Gypsum is a non-hazardous mineral.

Pure gypsum is a white rock but sometimes impurities colour it grey,
brown or pink. Its scientific name is calcium sulphate dihydrate and
its chemical formula is CaSO42H2O. This means that, for every
molecule of gypsum, there are two molecules of water.

If a piece of gypsum is ground to powder and heated, it will lose
about three quarters of its water. If this powder is then mixed with
water, the paste or slurry will set rock hard. The
chemically-combined water, previously removed, has re-combined and
the material has reverted to the original composition of the rock.

The powder is called hemi-hydrate gypsum plaster (Plaster of Paris).
Gypsum plaster has been used in buildings for literally thousands of
years.

Gypsum is found in every continent of the world.

From 1st April 2009 the guidance on landfill changed. Visible gypsum
waste can no longer be disposed to general landfill, but must go to
a separate cell for non-hazardous high-sulphate material. This is
because gypsum mixed with waste organic material can give off
hydrogen sulphide gas (bad eggs smell).

Bottom line Ms RER - Gypsum is a non-hazardous mineral.

Please check your info.!


#16

Here’s just one source of precautionary info: there are hundreds
discussing the inherent dangers from exposure.

http://www.cdc.gov/niosh/rtecs/mg2402c0.html


#17
http://www.cdc.gov/niosh/rtecs/mg2402c0.html 

That reference doesn’t make me worry much. Even injecting it into
rats takes a rather large dose to cause tumors.

I’m curious about where they got the inhalation data. 194 g is a lot
of gypsum to suspend in a cubic meter of air. I can believe that
breathing that mixture for ten years would cause lung problems.

Al Balmer
Sun City, AZ


#18
Here's just one source of precautionary info: there are hundreds
discussing the inherent dangers from exposure.
http://www.cdc.gov/niosh/rtecs/mg2402c0.html 

This is not any worse than any other finely divided dust which I
think everyone will agree is not a good thing to breathe. But it is
neither toxic or particularly hazardous.

The Permissible Exposure Limits are high, the NIOSH recommended
exposure limit in your citation is 5 mg/m3 time weighted for 10
hours

Just so that number has some reference that folks might be familiar
with the NIOSH PEL for grain dust (oat, wheat, and barley) is 4
mg/m3 time weighted for 10 hours

Jim

James Binnion
James Binnion Metal Arts