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Natural gold alloy


#1

Just used a customer’s gold that he had panned for with some
unexpected results. The raw gold as it came to me was in little bits
and flakes about 1 to 2 mm. I melted this into an ingot that tested
22K with my Tri Electronics GXL-24 Pro electronic tester.

This material I alloyed with United Refining white gold alloy #915
to 14K. Since I was starting with approximately 22K, there was
already 8 to 10 percent of some unknown metal in the gold.

I cast a ring from this. Not as white as I was hoping, but not
unexpected since I was not starting with pure gold. What was
interesting is that: 1. The metal cut and filed like butter. Not at
all like typical karat gold and especially not like 14K white. 2. When
soldering on a setting the molten solder soaked into the metal more
like a sponge than flowing on the surface and wicking into the joint
with caplillary action as we usually see.

The cast ring tested as 14K white. This intrument is + or - 0.5
karat. The ring turned out just fine. It was one of those thihngs
were the customer wanted to use his own gold and was less concerned
about color or exact quality.

My question is a matter of curiosity rather than trying to solve any
kind of problem. What is likely to be in that gold to make it behave
that way? Perhaps someone with experiece using panned gold has some
insights.

Stephen Walker


#2

I gave up using panned gold years ago. I had a customer that brought
in hislocal panned gold for a ring casting. I alloyed it down with a
bought alloy and cast a heavy man’s ring. There must have been some
impurity like lead, because it cracked every way it could until I
finally had to give up trying to solder it. Haven’t felt the need to
repeat that experiment again. I now will only use nuggets for
accents on a ring of known casting grain.

Janine in Hot Redding California, the middle of great gold panning
country.


#3

Hello Stephen,

I can’t answer this question for you but I did some casting years
ago with natural gold reduced to 18 yellow gold. I’ve tried to set a
stone in this ring and imagine how I looked when I tried to bend the
prongs. They just broke of !! No bending, no nothing, whatever I
tried to bend them smoodly, they all cracked when I applied some
force and even the shank which was much heavier then the prongs
broke.

After this big dissappointment, I did some research and found out
that the ironoxide caused this problem. Ironoxide is known as black
sand and makes gold very brittle. With this in mind I never ever used
natural gold before it is refinned and all tracks of ironoxides are
removed.

Just another experience I’d like to share. BTW, the gold came from
Spain and was imported from a guy who tried to sell his own natural
gold. One time happening and I learned my lesson well.

Enjoy and have fun.
Pedro


#4
I gave up using panned gold years ago. I had a customer that
brought in hislocal panned gold for a ring casting. I alloyed it
down with a bought alloy and cast a heavy man's ring. There must
have been some impurity like lead, because it cracked every way it
could until I finally had to give up trying to solder it. Haven't
felt the need to repeat that experiment again. I now will only use
nuggets for accents on a ring of known casting grain. 

Alloying native gold can make problems worse, since the alloys we
add already harden the metal, and any impurities in the native gold
will have more of an effect. Used as is, many native golds are quite
workable. During the California and Alaska gold rush periods, miners
often had much more native gold, than they had normal spendable
money, since coins and bills had to be imported from the east, and
often were in very short supply. In the case of California, until
the establishment of the San Francisco mint, it was common practice
for local jewelers and other businesses to take native gold, make
their own coining dies, and issue their own private coinage. These
were not legal, government approved or issued coins, but the area was
still a territory, and the stuff was in wide use. Much more
convenient to have a little coin that was worth a dollar than to have
to weigh out your gold dust at the saloon.

The range and variety of these California gold coins was fascinating
and large, though many are quite rare, since the majority was turned
in to the newly established mint when it was built, and circulation
of the private coins became illegal after the government made coins
were available. After my father retired from his job as a research
chemist, he found numismatics as a hobby, and found and specialized
in especially, the small denomination (a dollar and under) cal gold
coins. Some are very rare varieties, with only a few examples known.
Others are more common. Many state “california gold” on the coin (or
alaska gold in that case)

In most cases, the actual maker is unknown, but jewelers and a
number of other metal working trades were involved, and some of the
coins are just wonderful little pieces of hand cut die work and
minting skills. For the most part, these coins were generally made
directly from the native gold, not from further refined gold. This
was practical since in both the california deposits and the Alaskan
ones, the purity of the gold found tended to be quite consistent,
and these native alloys worked quite well. In both, the main alloying
metal is silver. But there can be traces of copper,lead, iron,
arsenic, and other things, all of which would have an increasing and
sometimes nasty effect on the workability as you alloy the metal down
to lower karat.

The california gold deposits generally tended to be about six
percent alloy, if I recall right, while the Alaskan deposits were
higher gold content. For my dad, this was part of the fascination.
After he retired, he still had full access to his old lab facilities,
which happened to include X-ray fluorescence equipement. So he was
able to non-destructively test these coins for their alloy content,
which made it much easier to identify which were real, and which
were fakes or later reproductions (the victorian age found these
fascinating as tokens and small jewelry items, and there were, as a
result, many copies made in lower gold content. Some were made as
deliberate souveniers, and some of these were labeled as “tokens”, so
there was no deception. The cal gold hobby for my dad turned into a
business, and by the time he died in 2000, he was one of the best
known dealers and experts in these little gems of coinage art, and
his collection of the the best in the world. Not as hard to do as
some types of numismatics, since these were coins from a specific
narrow geographic and historic period, but still, it was impressive.
But anyway (yeah, remembering my dad gets me going sometimes…) He
was passionate about these things, and it fun to sometimes pass on
what little of his passion I know a bit about…

Nuff rambling.

By the way, of the various sources of native gold you commonly see
on the market, nuggets from australia are often substantially higher
in gold content than either california or Alaskan gold. 98 percent or
so. And so are some of the nuggets found in the eastern U.S. Not many
people know it, but prior to the California gold rush, the gold
action was in places like North Carolina. Some of the finest and
largest specimins ever found were dug up in that part of the
country, and from what I’ve been able to glean, there’s likely still
a lot of gold in the ground there. It got abandoned and forgotten in
the California and Alaskan crazes, but it’s still there. Somewhere…

And also by the way, if anyone happens to be interested in
purchasing a really pretty Australian gold nugget weighing about 3.5
ounces (roughly two inches across), with some rather pretty
crystalization in some parts, rather than the water worn look of many
of the alaskan and california specimins, let me know. It’s a piece I
got from my father. Kind of unusual, larger than most specimins you
see for sale. I’d hate to just send it to a refiner to melt down or
dump it on ebay, so I’ve not sold it yet. But I could kinda use the
cash these days… If some collector reading this is interested and
would appreciate having such a specimin, reply via private email. I
also think I’ve got a few of those small cal gold “tokens” (either
the fakes, or real coins that are damaged enough, usually from being
soldered to a pin or something, as to no longer have numismatic
value. Fun, but not worth a lot. If anyone is interested, let me
know.

Peter Rowe


#5
After this big dissappointment, I did some research and found out
that the ironoxide caused this problem. Ironoxide is known as
black sand and makes gold very brittle. 

The ring turned out just fine, or so I thought. Rhodium took care of
the color. After reading these several comments and also getting some
off-list advise from a metalurgist I gave the sprue a twist with some
pliers and it broke right off the button! Apparently the nice cutting
properties come with a cost. I will have to advise the customer to be
careful.

Stephen Walker


#6

In my practice I use natural placer gold which I melt and use to
fabricate jewellery. I have found that not all placer gold works for
this purpose. I believe problem is zinc in the natural alloy; in
this case the resultant gold is brittle and difficult to impossible
to roll without cracking. However, some gold works beautifully, and
is very similar to 24k gold to work with. The gold I usually use
(from our family mine in the Yukon) is a natural 20K alloy - I don’t
re-alloy it, just use it directly. The gold from each source is
different, and you must try it to see if it will work - you were
lucky that the gold you were given to use was satisfactory.

Leslie Chapman
Fortymile Gold Workshop


#7

In my experience, some placer gold works just fine and some doesn’t.
I buy it occasionally, using it mostly for bezels and accent wires
and such. One batch of three ounces or so, approximately 22k, when
melted into an ingot, cracks as it is being rolled out. On the other
hand I have some ten ounces of very fine placer gold from a creek
North of Fairbanks which is a dream when it comes to rolling and
drawing. This gold also is about 22k. I suspect that the first batch
is slightly contaminated with mercury. Some of the gold I have
obtained over the years came from creeks which have been worked over
and over in the past. I suspect that mercury, which is used in the
reclamation process, is lost back into the stream with small pieces
of gold which is washed through the sluice.

Jerry in Kodiak


#8

I was asked to make a set of rings for a geologist who discovered a
gold mine in Cripple Creek, Colorado. He wanted the rings made from
the gold unaltered, and gave me a core sample straight from the
mine. I made an ingot of it. I asked him to assay it for me and it
was about 21K with some bismuth in it. It was so malleable that it
was difficult to get it exactly the right size…as I hammered the
rings on the mandrel, the slightest hammering with a rawhide mallet
stretched the ring larger than it would have ordinarily stretched
using a standard alloy of that karat.

Elizabeth


#9

When I had a retail shop several years ago a young couple (very early
20’s) walked in to look at jewellery. The young man got aroung to
telling his girl how he, at one time, went out and found some pure
yellow gold. I don’t know that he felt that this made a suitable
impression on her so he continued that what he really wanted to find
in the wild was some white gold!!

Roger