Field testing for microgems

Jewelry Discussion
1

Like many prospectors around the world I often find myself with a
handful of grit containing many small and colourful crystals less
then 1 mm in diameter.

With more then 95% mountain in a terrain twice the area of Japan and
known commercial diamond and emerald finds elsewhere in Canada, why
would BC not expect to some day boast deposits of these gems as well
as sapphires, rubies etc?

If a smart gemologist could come up with a kit for cheap, easy and
reliable testing of microgems in the field thousands of us would be
most appreciative.

2

Hi piper,

Have you used the S.G liquid test Its easy and fast for the sizes
you mentioned just drop stones are stir, the sapphires will sink the
rest will float.

Ahmed shareek

3 
If a smart gemologist could come up with a kit for cheap, easy and
reliable testing of microgems in the field thousands of us would
be most appreciative.

While you probably can’t get refractometer readings from such tiny
crystals, the fact that they are still crystals means that with a
microscope you can tell a lot simply by the crystal habit. Combine
that with a polariscope, or polarizing filter for you field
microscope (which for that size crystal, need not be a fancy
binocular gemological scope), and perhaps a set of specific gravity
liquids (which work equally well with standard sized gems and sizes
almost down to fine sand size), and I’ll bet that with some more
mineralogical/gemological training, identifying many of those
crystals would not be as difficult as you think. And in the above
set, given that you don’t need the high cost microscope, but rather
any decent student grade monocular scope with transmitted light, the
cost shouldn’t be prohibitive. The SG liquid sets are small enough to
travel with, and not outlandishly priced.

Peter Rowe

4

Thank you - and also Ahmed. If E&M Minister Neufeld will give us
free miners such a kit for Christmas we could see a rebirth of
prospecting in BC.

Does anyone see any reason there might not be diamonds, emeralds,
rubies and sapphires in BC?

5 
Does anyone see any reason there might not be diamonds, emeralds,
rubies and sapphires in BC?

probably not diamonds. At least not primary deposits, or at least
not in that portion of BC that’s the Rocky Mountain range. Those
mountains are too young. Kimberlite pipe volcanos, the source of
diamonds at the surface, generally tend to date from the jurrasic or
earlier. They’re old. You’re not likely to find even remnants of
those in the Rocky Mountain areas themselves. You might find some
alluvial diamonds brought down from more northern regions by the
glaciers, though.

Your others generally need either Pegmatite Dikes (the
beryl/emerald, etc), or metalmorphic zones, and both of those might
be found in the Rockies or nearby areas.

just remember that gems, like any mineral types, don’t just occur by
chance in any old place. Research the needed geology for the gems to
form, and research the geology of a region you’re looking in, and
you’ll have a better idea of which areas to prospect in. Looking for
igneous or metamorphic gems in an area where the local rock is
millions of years worth of undisturbed sedementary deposits, for
example, is likely to be unproductive. Do your homework.

While you’re at it, learn enough basic mineralogy so as to allow you
to know how to identify the minerals/gems you’re looking for.

Without the “homework”, you’re tossing darts, blindfolded, at a very
big target with only small selective bullseyes.

Peter Rowe

6

You most likely won’t find diamonds in BC because it is a
geologically active area. Diamonds have been found in cratons. A
craton is the old and stable part of the earth’s lithosphere. Think
of the older part of continents. Diamonds have been found in Canada,
but not near the Pacific rim.

As far as corundum, I’m not sure. Perhaps some of our other
gemologists or geologist can speak to that.

Mike DeBurgh, GJG
Henderson, NV

7

Kind of off topic but possibly of interest:

Speaking as an ex geologist, diamonds are found in kimberlite pipes,
and the weathered products from these pipes. Quite a neat feature as
they are rarely more than a few hundred meters wide and the thinking
when I was at uni (1995) was that diamond can only form at immense
pressure but relatively low temperature, conditions found where the
earth’s crust (the solid bit) meets the lithosphere (the semi liquid
bit) under large mountains, and to then get these to the surface you
need them to transport quickly to keep the crystal structure, the
surprising bit is that the speed needed is about mach 2, the same as
an ICBM.

No one has ever been around when a kimberlite has been formed (a
100m wide pipe of lava bursting out of the ground at twice the speed
of sound, it is the kind of thing you would hear half way around the
world and would make Krakatoa look demure), and luckily they seem to
be a feature of a very early earth, so not something we need to
overly worry about. Kimberlite pipes tend to form in concentrated
fields, one is obviously at Kimberly in SA (hence the name), there
are a bunch in Canada (Saskatoon, if memory holds, but doubtless
other areas),bits of Eastern Europe and other spots in Africa - as
Mike said, it needs to be an old bit of crust that is, or was once, a
mountain.

They way that people search for diamonds is to find what are called
“indicator minerals” for these kimberlites, these are generally
certain kinds of garnets which are relatively easy to id using a
loup. I did think about heading into that field, but it is mind
numbingly dull, so I opted for gold exploration in West Africa
instead (at least you occasionally see what you are looking for
then).

Other gems are different though, and are usually created by
metamorphic processes (lots of steady heat and preassure over 100s of
millions of years) causing large, pretty crystals to form, Sri lanka
is a good example of this sort of thing. No idea about field testing
though, good luck with that one J.

CP
Collarsandcuffs.co.uk

8

What is the mean and SD for kimberlites across Canada?

Speaking of exo geologists, what do exo geologists say about
strong-C formations off-planet?

What kind of gems do the great volcanic fields of the Moon yield?

9

Peter,

What kind of gems do the great volcanic fields of the Moon yield?

At the risk of sounding uncharacteristically intolerant, I’d first
wonder just how the heck you think we’d know since none of the moon
landing missions did extensive gem prospecting there or anywhere else
(and lava generally is not known for extensive formation of mineral
crystals…), I’d secondly wonder just what you’re planning to do
with that knowledge (going there soon?), and thirdly, I’d wonder just
how many of these horses you’re planning to beat to death here.
While I’m all in favor of a thirst for knowledge, I’m beginning to
think that some of your myriad questions are sounding a bit silly.
Have you tried Google? How about Giggle?

You’re just beginning to sound like a Troll…

Or at the least, a bit like the little kid who replies to any
explanation with an endless sequence of “why”.

OK. sorry if I’m being intolerant or unreasonable. But for some odd
reason, these questions are kinda starting to annoy… It seems like
you’re cooking up questions to ask without having made any reasonable
effort to research whether they make sense or are reasonable
questions before plopping them in front of the group. Diamonds in
shale? On the moon? Huh? What gives, dude?

Peter Rowe

10

Peter,

I think if you are truly interested in this then it is time to take
Geology studies in University, and use Google a bit.

For example you were asking where in Canada typical geological
formations appear, on the first page of a simple Google search
yielded

http://tinyurl.com/ye2pc2s

This should provide a gateway to your

Here we mainly concentrate on what to do with stones after they have
been formed / Mined, not finding them. There are other and better
discussion boards on that subject.

Good luck on your studies, and possible prospecting

Kay

11

If that is the moderator’s wish, then may I suggest
BC-Free-Miners-And-Masons at yahoogroups

I am not a “possible” prospector. I prospect now. I did a year of
geology at Carleton U in 1962 and then prospecting in NWT where I
also worked at Camlaren, Giant, Discovery and Viking gold deposits.
You can google on them. I am mostly self-taught. I take courses here
and there. I took a gold panning short course at VCC and was
fortunate to have a fully qualified geologist as teacher. He said to
always look at the glassy crystals in the pan. But what good is that
if you are not a jeweller and a very advanced one at that?

Mr. Neufeld, cc’d, is E&M Minister of BC. Here is my submission to
him.

If a hobyist rockhound tourist or prospector finds metallic crystals
while prospecting, it is easy and not too expensive to have an assay
done. When glassy micro-crystals are found they are very difficult
and expensive to assay. Can he remedy that?

How many generations of rockhounds saw the tiny glassy diamonds at
the roadside rock cut near Wawa Ontario before somebody assayed and
found out what they were? It is gold territory so I am sure there
were lots of curious people. Did I even see diamonds in NWT as I was
not so far from present kimberlite mines?

On the Moon, the orange dust at Shorty crater was only .04 mm in
diameter. How big were the green crystals found elsewhere? Glass yes,
but so are Be family gems. I have some tiny amazingly green crystals.
What are they? They are in a mixed sedimentary and volcanic
formation, often found here in BC. I cannot tell for sure if the host
rock is igneous or metamorphosed sediment. The shales blend in and
mix in with a lot of other material. Some small strata are even clay.
Paleoclay? Some strata look like ancient volcanic dust consolidated
and sometimes these are unconsolidated. Loose sediments of ancient
volcanic ejecta? The extreme green stone flouresces to a very bright
blue but not the matrix. I have too little to determine SG, scratch
etc. So my guess is that very costly reflection/refraction testing is
needed and only a gemologist trained beyond that of the average store
shop jeweller would know.

I found a low grade Re hardrock ore deposit. Re is now the 7th PGE.
The only Re mineral I know of is a sulfide found in Russia. In the Re
hardrock there were a few tons of fine loose sediment which looked
like beach sand but I saw it contained many tiny glassy crystals
under the glass. Paleosand? Maybe dinos stomped on those sands 130
mya. No problem assaying the Re but the crystals? And why not Re
bonded with Si in a new gem? Is there even one jeweller in Vancouver
who could identify a rare Re micro-crystal?

What about those tiny glass cystals on Moon? Are some diamonds?
Surely. If impacts cause the flash-formation of diamonds then there
must be diamonds on the Moon. What other gems are in its regolith?
Given that the regolith is mostly basalt-like, then it contains the
whole Periodic Table we see here on this planet. Be and Si and Al?
Yes. Flash-formed emeralds as well? I would expect it.

What happens to the agglutinates in the dusty sediments of the Moon
when an asteroid strikes? What gems do the plutonic forces create out
of the sediments? Since there are some newly named Moon minerals now,
maybe some Moon stone precious gems will show up some day in BC
jewelry shops.

12

Still searching for micro gems ?

Why not Geo chemical or Geo botanical prospecting ? Geo chemical
prospecting involves soil samples. Geobotanical prospecting involves
plant samples or even taking plant species counts for a geographical
area. These are plotted on maps to show areas of greatest
concentration.

I examined this as an undergraduate in 1970. The Russians have been
doing this since the 1950’s Google had 3800 listings for
"Geobotanical prospecting for nickel" AND 3,000 LISTINGS FOR
Geobotanical prospecting for DIAMONDS.

Google had 15,700 listings for Geochemical prospecting for DIAMONDS.

Diamonds have the characteristic of being accompanied by Nickel, so
follow the nickel.

The presence of nickel can be determined by eye for a rough field
test and calorimetrically for a more refined lab test Google
"Dimethylglyoxime reacts with nickel ".

I goggled some 500 listings for "Nickel and Diamonds in Peridotite"
THERE WERE MANY MORE LISTED.

Please return when you have something to share

Robb.