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Glass of water in showcase

Why do Shop put a glass of water inside the showcase - where the
jewellery and gems is display - i been pondering what the real
meaning to that

Why do Shop  put a glass of water inside the showcase - where the
jewellery and gems is display 

For the opal. Showcases’ can have a very low humidity with the
lights and semi sealed interior. It is a brutal environment for
some opal. The glass of water, or a small tray of rough opal in
water as a display is a means to add a little humidity to the case
and hopefully retard or eliminate spontaneous cracking of the opal
in the case. Don’t know it if it works, but the technique is highly
recommend by the Australian opal community.

Don ( and I apologize for my fubar on the acid/water post.)


In my experience, I have most often seen glasses of water placed in
showcases that contain ivory items.(in museums, homes and giftshops)
It is done with the belief that it will keep the ivory from

Ivory is made up of organic (the part that grows) and inorganic (the
hard, wear resistant part). It is very susceptible to fluctuations
in relative humidity. It will warp from too high of humidity (or if
immersed in water- a major no, no.) and it will crack and delaminate
from being too dry. They are many recommendations circulating out
there to prevent this including; placing containers in the display
cases and applying oils and waxes. As a museum curator in my
professional life, I’d would highly recommend against using water in
the cases or applying anything to ivory objects. The risk of
damage far outweighs any benefit you might gain. Unless the case is
airtight or very close to it, it isn’t going to raise the RH
significantly. And, furthermore, if you don’t have any accurate way
of measuring it, how would you know if it is at optimum or at
damaging levels? Plus, by placing water in the case, you risk
damage from spilling and corrosion of metals and other materials in
the case. I’m sure there are a lot of people out there with anecdotal
info on how it kept their ivory from cracking but it is more likely
it has been kept in a relatively stable environment with gradual
fluctuations, out of sunlight and away from sources of heat and
moisture. (can you prove it would have cracked if you haven’t used
containers of water?)

The best recommendation, keep ivory (and most everything else, esp.
organic materials, for that matter)out of direct light, away from
sources of heat (watch those spotlights, they can really cause heat
buildup in a closed case), and dust free. Put in ziploc-type bags ,
not in contact with materials that can stain it, when storing. And
whether storing it or displaying it try to keep the environment as
stable as possible. Avoid big swings in temp and humidity. Plexi
domes and cubes with tight fitting bases are good…they will
buffer the changes occuring outside it. Of course, these aren’t
great in retail situations.

In addition, I’d be very careful what types of fabrics I used in
showcases. Avoid anything with wool in it. It naturally off gasses
sulfur which, as jewelers we all know, tarnishes silver and other
metals. Stick to 100% polyester, which is inert, if possible.

My experience and plenty of sound controlled experiments support my

Okay, off my soapbox. I hope you and other “Orchidians” find this
info helpful. I certainly have learned a lot, been entertained, and
drawn inspiration from everyone’s contributions. Thanks and Keep Up
the Good Work Everyone!

Chris H.
Ketchikan, AK

1 Like

Oh yeah, I forgot about opal. The same recommendations apply here.
Keep in mind, it is the rapid environmental changes that are most
damaging. What if you keep it in even a perfectly controlled exhibit
case and then sell it? As soon as you pull it out of a “perfect
environment” into the “real world” you are potentially giving it a
big shock. What if the person buys it in wet, Ketchikan , Alaska
and then gets back on their cruise ship and later flies home to dry,
Palm Springs? You see what I mean.

Again, I’m not an opal expert, but I’m sure many will have stories
about how they put water in the cases or coated their opals with
something and they never cracked or crazed. Well, I’d have to again
ask, “How do you know they would if you didn’t do anything?”

I’m by no means an authority on opals but if it is that “delicate”,
is it suited for jewelry, esp. with the “general public” ? (as
opposed to a collector who might take more steps to keep their
valuable and environmentally sensitive gems in a controlled

Obviously there is no simple solution. But, in most cases, the less
you do the better. Pick the most stable material possible to use in
your jewelry. Educate the buying public that even though it is
"rock" , it isn’t indestructible and may require special care. Just
like the discussion on gold in chorinated pools, it pays to educate
your customers so it doesn’t come back and bite you.

I don’t pretend to have all the answers to artifact/stone/jewelry
preservation , but I have studied the subject for a number of years
because of my work. But, hey, life’s a continual learning process,
so you know of some scientifically derived data that says
otherwise, please let me know and cite your sources.

Again, I hope I have provided some food for thought.

Chris in Ketchikan