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Porosity of gem stones


#1

May I ask a stupid question? Has anyone done scientific porosity
testing for gems like diamonds, sapphires, rubies and opals? I ask
because I have been amazed at how sponge-like some of my slate family
samples are. Amazed too because dimension stone slate is used as
flooring.

Perhaps it does not have much practical value except that porous
stone would also be a sponge for colourants in water solution. Given
that turmeric spice is used in Asia to stain hard wood floors, maybe
it would also stain stone floors. And the dry stones I am now having
installed by a mason as house siding could gain a lot of weight in
the rainy season.


#2

I believe they use a sealer on stone floors, perhaps counters too. I
am sure marble requires something of the sort.

Rose Alene


#3

I have claims on two “dimension stone” deposits and I am testing out
their potential so you make a good point about sealers. Sealer
effectiveness needs testing too and I have yet to do that. Buyers
could use info on sealers and my guess is that there is a stone type
x sealer interaction.

I put a few 1-2 gram chunks of stone in water after weighing them
dry and weigh them after overnight soaking too. They always gain
weight. But remarkably they LOSE weight too. So it is NET weight that
is the final result.

What I envisage then is that if I had a microscope view on these
stones they would look like a kitchen sponge or maybe a mountain side
with a lot of cave openings and tunnels. But these are different
pictures.

In either case though the “solid” stone holds fine loose minerals
and it washes out when it stands in water.

I also did a test by accident. I had a collection of pretty red
chalcedony stones so I got a golfish bowl to diplay them. The water
got slightly murky after a few months so I thought I would outsmart
the algae (my guess) and I added some chlorine. Now after a few
months the water is filled with ghastly scum which the chlorine has
extracted from the stones and it is much worse than before.

Is this important to ornamental stone work? Yes. I also started
building a backyard pond this summer. I notice that some river stones
look great under a foot of clear water but quite mundane when dry.
The problem is to keep the water clear.

Does anyone on Orchid have microscope pictures of the “caveworks” in
jades and slates and chalcedony in particular?