Peter – This is interesting – why distilled water? Why water?
Wouldn’t it just move out of the pores at the first hint of heat
from polishing??? And then what does the diamond compound do? I
know nothing about cutting, polishing, etc.
stones --obviously…!
Laura.
lwiesler@att.net
Laura, I prefer to use either distilled or filtered water because
of the level of (potentially caustic) chlorine in our area’s tap
water. Water is ideal for saturating stones before cutting
because, unlike the oil that I use as a cutting lubricant, water
will evaporate quickly after the job is done. Water fills the
pores in the stone, and prevents the absorbtion of potentially
discoloring compound and oil. When you polish with diamond you
don’t generate much (hopefully almost no) heat. That makes
diamond ideal for softer stones such as Lapis, Turquoise and
Malachite - which have an annoying tendency to crack when exposed
to high temperatures. These are, of course, my own biased,
individualistic opinions. Other folks on Orchid will undoubtedly
disagree with my thinking…but knowing the quality of the
people on this forum I suspect they will do so in a way that
stretches my understanding. That’s what I love about this place!
Best regards from the now-sweltering-hot Cradle of Winter,
Pete
Buffalo, NY
I find that stones can get quite hot using diamond, hot enough
to melt the dop wax holding the stone.In fact, I no longer use
dop wax if I will be polishing with diamond- I crazy-glue the
stone to the head of a nail and use the nail as a dop stick. I
like diamond particularly for stones which contain areas of
widely varying hardness, like chrysacolla and yowah opal. The
great advantage of diamond over tin or cerium oxide when working
these stones is that it has a much lesser tendency to undercut.
Also, the various oxide polishes may discolor a porous stone,
whereas diamond will not. IMHO.
Lee
Was: Polishing agatized dinosaur bones
What does one use to polish Lapis? I have fair to middling success with Zam. But I've seen polished Lapis look much better at shows.
Since we can’t see those lapis stones you refer to having seen at
shows…
At the risk of being redundant John Sinkankas in “Gem Cutting”,lists
lapis lazuli pp. 266-267, suggests leather with Linde A or chrome
oxide. And Linde A on tin for faceted lapis. You don’t see faceted
lapis very often.
Rick
I read somewhere that waxing is a treatment for Lapis, I have never
tried it though, I use Linde A and it seems to work fairly well, know
what you mean though, I have seen some stuff at shows that looks like
it is still wet.
Terry
Lapis is most often waxed. I don’t wax. I’m a stickler for natural
just coming to grips with heat treating. And I’m sorry I can’t
recall my wheel designations. I think I just stop at 600 (well worn)
on Lapis, Sugilite and DinoBone.
If someone has a better treatment PLEASE contribute.
TL Goodwin
Interestingly, I have faceted lapis and polished it with Linde A on
wood…maple is a bit too dense…I have a custom made teak wheel
I use. Haven’t done it for a number of years though.
The Sinkankas reference simply says ‘leather’ but does not specify
what kind!! My experience says hard cow leather about 1/4" thick does
the very best job. I also have another teak wheel with grooves and
get good polish on cabs with that, though size of the stone and
groove limits its use. Make your speed about 4-600rpm if possible.
Lapis is not like jade which likes about 800rpm. Don’t use too much
pressure as lapis lazuli can fracture ( again unlike jade which loves
pressure and heat during polishing).
Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry!
I am a Lapis nut. I have used Zam, Linde A, etc I also facet and
Cab. Chunky facets. Free form cabs. I use Hi-Tech Sanding and
polishing pads from 180-350-600-1200.
Then eastwind lapidary dimond pads from 3000-14,000-50,000. No more
Zam, Linde A or mess, nice and clean.
These are all flat pads cooled with water on a 8inch Hi-tech flat
lap and I finish with a buff and wax with Renaissance wax. This gets
me a water shine everytime. The wax is more for seal and finger
print protection and final bling.
One of the well known lapidary cutter on the orchid - Doug I think
suggested this rout for a ruby problem I had, which worked great, so
i used it for my other lap work and it worked great.
I would like to add my tcw to this thread. Although Sinkankas’ book
is a great resource for faceting and cabbing I have found a huge
amount of info explained just ever so slightly differently in
Christopher E Hyde and Richard A Matthews’ The Complete Book of Rock
Tumbling. This book has been invaluable to me as I have taught
myself to cut, grind, create performs for tumbled finish and hand
finishing, created pounds of hand broken tumble loads and so on. They
do a wonderful job of thoroughly explaining processes, gives all
kinds of technical and machine info, almost as good as Krey T’s
website! This book even takes you into the finish work of what kinds
of settings and uses for your finished rock and the basic steps to
creating them. For newbie’s in lapidary work or for someone just
adding that as a part of the whole jewelry making process this book
would serve you well. I found mine for cheap on eBay but even new it
would be worth the investment. Cori in Wisconsin where the rocks are
still frozen to the ground!
I’m a Lapis nut myself- love the stuff.
I go diamond all the way up to 100,000 diamond grit, and use a 3M
cerium oxide belt (white belt) or pad after the 3,000 Nova wheel.
After the cerium oxide I use 4" muslim buffs (blue, stitched) charged
with 50,000 and 100,000 grit diamond. Wash w/soapy water and rinse
between the 50,000 and 100,000 grits though. Works wonders, no wax
necessary. Does wonders for grade “B” and “Denim” Lapis too.
I cut lapis from rough cutting to pre-polish on diamond wheels. Lapis
is soft so I start on a 600 wheel and work through to a 1200 wheel. I
then do the final polish on a leather buff with tin oxide. Tin oxide
is a bit messy but seems to give a good polish.
Rosslyn
Adelaide.
After the cerium oxide I use 4" muslim buffs (blue, stitched) charged with 50,000 and 100,000 grit diamond.
Diamond on stitched buffs? I don’t believe I’ve ever heard of using
diamond on something with so much surface area (between the muslin
layers)-- it always seems to be felt, wood or leather. Doesn’t this
soak up an awful lot of diamond?
Noel
Hello,
New to Lapidary, mostly learning through trying on my own. Is it true to not cut/grind/polish lapis lazuli with water because it will release sulfur? What about black tourmaline?
I was told to cut/grind/polish stones with water to keep them cool…thoughts? What stones should not be worked with water?
Does anyone have a good source recommendation for stone toxicity, please? I have Gem Cutting by John Sunkankas but there isn’t any information about stone toxicity and safety practices.
Please share any insight, it would be very much appreciated.
Thank you!!!
Congratulations on starting your lapidary adventure. What you seem to have heard about lapis is not true. If your lapis has pyrite inclusions, which is pretty common, you’ll notice a smell of sulfur when you cut it. But you still need to use water while cutting and polishing it, or any stone. I don’t think the water has an adverse effect on the pyrite.
Stone dust is often toxic to inhale, since many of them contain silica, and often other substances that are more acutely harmful than that. You need to research them on a case-by-case basis. Some things to look out for are arsenic, metals like copper and cobalt, beryl, and radioactive materials like uranium. While the use of water keeps down the dust, inhaling mist laden with dust isn’t much better. It’s advisable to wear a mask when cutting stone.
Here we go! This is the best advise yet. I was going to say tin oxide, always worked great for me. I also use an expanding drum with a leather wheel on it. you’ll need soome water spray to keep things cool and create a paste with the tin oxide. If it’s to rough, you’ll need to follow others’ advisse and use a sanding wheel first.
Cheers!
I have to agree with anthony about lapis being a multimineralic stone rather than a pure mineral. as a consequence there are areas that are going to be very soft, especially white with calcite, and other areas that at harder. I would stay away from rouge or anything that can discolor it. the stone is porous and will take up impurities and discolor easily… depending on the quality of the stone, it may not take a high polish.
you need to use water to keep the stone cool when cabbing and polishing… when cutting slabs for cabs, use water rather than cutting oil…the latter makes a mess… the former causes rusting so a slab cutter has to be kept clean and dry after cutting… trim saws use water… doing dry grinding and polishing risks friction heating which can cause burn marks and even small cracks…water is the best to keep the stone clean and cool when cutting and polishing. for the final steps in polishing, you have to go dry… but still be careful of heating… if the stone feels hot, it is hot…it doesn’t matter what polishing agent you use… all will cause frictional heating… even a clean felt or cotton wheel without polishing compound causes heating.
silica dust exposure causes silicosis, an irreversible lung damage… if you really want to be safe, use an N95 or N100 mask that catches 100 nanometer particles…some serptinites carry asbestos particles that are as small as 10 nanometer… grinding stones outside is preferable than inside even with ventilation.
Good quality lapis has pyrite in it… poor quality has calcite… the rest of the blue is caused by lazurite, sodalite, nosean and related sulfur containing minerals. the presence of calcite can make polishing difficult… calcite is very soft and wears away faster leaving pits and grooves…
Cobalt salts are toxic… beryllium metal causes irreversible lung damage: beryllosis… beryl itself is inert except for fine dust, which is a silicate dust… arsenic, mercury, lead, and other heavy metals shouldn’t be a problem unless you are cutting soft metallic minerals… uranium and thorium are associated in high concentration with rare earth minerals… the amount of uranium in zircon is not high enough to cause problems… even though zircons contain enough uranium that they are key geologic indicators to the ages of rocks… the oldest rocks on earth so far found are dated by the uranium/lead ratios in zircons… going back to the early archean and late hadean periods… 4 billion years ago…copper is generally non toxic… it’s an essential trace mineral for life… too much copper by ingestion causes a zinc deficiency and vice versa…
I need to add that berylliosis is NOT caused by silicate beryl but by metallic berllium. Beryllium in beryl is bound tightly to silicate. Metal beryllium causes both acute and chronic toxicity which is irreversible and caues severe lung damage. There is no treatment, Copper and zinc are essential trace elements for health. The same protein transporter in the gut takes both zinc and copper into the blood stream. too much zinc or too much copper leads to a deficiency of the other metal… taking excessive zinc supplements to treat common colds can cause copper deficiency which causes nerve damage. However, this only applies to ingested copper and zinc.
For general purposes no one needs to worry about silicosis or beryliosis as these are consequences of industrial exposure. I still would recommend doing lapidary work outside and upwind of any dust or spray, even if indoors has ventilation.,. especially if you are going to do dry grinding which is dangerous for stones due to overheating by friction,… your concerns are well taken… people who work with potentially dangerous chemicals, fumes, and dust should take precautions. Radioactive materials pose less of a problem unless the minerals being cut have ore concentrations of uranium or thorium. Heavy metals are the same… ore concentrations… that does not mean that these materials should not be handled with caution… If anyone would like to know more about toxicity, they should post me. I do know more that just a little about rocks and minerals and health… I am an associate member of the American Geophysical Union and also an MD…