Iridium

Metallic tectite was my first thought on seeing it today.

I don't think a housefire or campfire would ever reach the required temps to melt it if it had originally been a jewellery piece, and iridium jewellery seems to be a very new development.

Amazing find if it's a natural specimen.
 
EM - do you recall where you found these? If so, do you know anything about the industrial history of the area they were found?

These are too regular in shape, and too pure to be anything but man-made, IMO.

Here's my wild-ass guess ... fountain pen nibs :o

If you look at the Wikipedia article for iridium ( http://en.wikipedia.org/wiki/Iridium ), you'll see mention of iridium being used to tip gold nibs for fountain pens. So my guess is that when nibs wore out, pen makers would melt the old tips to recover the gold for reuse, and some how separate the iridium "waste" from the gold??? So I think you have a couple of nuggets of iridium/gold alloy recovered from melting down old fountain pen nibs! Just a guess, feel free to shoot holes in it!

By the way, there's an interesting paper called "A History of Iridium" referenced by the Wikipedia article, well worth a read if you have time: http://www.platinummetalsreview.com/pdf/pmr-v31-i1-032-041.pdf

Cheers.
 
Holy Smokes , Nice find EM and as usual thanks for sharing! I cant believe knowone guessed iridium considering it is the name of the thread. I am no expert on PGMs , but I think this alloy is very rare as I do not think Iridium and gold are that heavily associated and even more surprising is that the xrf did not pick up more trace elements, but what they say about gold it is where you find it. I also believe it is heavily speculated that most if not all Iridium on the planet is extraterrestrial in nature. Anyway Very very Cool! I am jealous
 
goldpelican said:
Metallic tectite was my first thought on seeing it today.

I don't think a housefire or campfire would ever reach the required temps to melt it if it had originally been a jewellery piece, and iridium jewellery seems to be a very new development.

Amazing find if it's a natural specimen.
Click to expand...

Iridium Jewelry? I have not heard of Iridium jewelry as it is usually too brittle, it is a very common alloy with platinum jewelry usually no more than %15 and the other is Rhodium.
 
The thread was renamed after it was revealed.

Iridium jewellery is new - there's a few websites selling it as a specialty.
 
goldpelican said:
The thread was renamed after it was revealed.

Iridium jewellery is new - there's a few websites selling it as a specialty.
Click to expand...

We asked Peter Davis ( as he tested it ) , as far as he know's it's never been used in jewellery .
He couldn't think of any industry it would be used in .
 
goldpelican said:
The thread was renamed after it was revealed.

Iridium jewellery is new - there's a few websites selling it as a specialty.
Click to expand...
OH that makes sense , at first I thought DUh!

Wow Iridium Jewelry I have been out of the loop for a bit, busy with my new baby girl (6 months now) I will have to ask my casting guy about it see if I can make something with it. Do you know what it is alloyed with?
 
spannermonkey said:
goldpelican said:
The thread was renamed after it was revealed.

Iridium jewellery is new - there's a few websites selling it as a specialty.
Click to expand...

We asked Peter Davis ( as he tested it ) , as far as he know's it's never been used in jewellery .
He couldn't think of any industry it would be used in .
Click to expand...
Iridium is used as an alloy in platinum jewelry and sometimes palladium, it is also used in spark plugs and probably several other industrial apps like catalyst , never heard of it alloyed with gold.
 
whinfell said:
EM - do you recall where you found these? If so, do you know anything about the industrial history of the area they were found?

These are too regular in shape, and too pure to be anything but man-made, IMO.

Here's my wild-ass guess ... fountain pen nibs :o

If you look at the Wikipedia article for iridium ( http://en.wikipedia.org/wiki/Iridium ), you'll see mention of iridium being used to tip gold nibs for fountain pens. So my guess is that when nibs wore out, pen makers would melt the old tips to recover the gold for reuse, and some how separate the iridium "waste" from the gold??? So I think you have a couple of nuggets of iridium/gold alloy recovered from melting down old fountain pen nibs! Just a guess, feel free to shoot holes in it!

By the way, there's an interesting paper called "A History of Iridium" referenced by the Wikipedia article, well worth a read if you have time: http://www.platinummetalsreview.com/pdf/pmr-v31-i1-032-041.pdf

Cheers.
Click to expand...

I had a look at Wikipedia. Interesting theory whinfell. Happy to hear all ideas suggestions theories or geology about Iridium.

Fountain pen using Humans would have lived and/or worked in this area at some stage, but then again the same goes for everywhere Humans have lived or worked up until the 1950s.

It was found in mineralised gold bearing ground not far from top of a gully. I also found some old (but not dated) buttons and a silver cufflink in the area. Possible people living in the area from 1850s until the 1930s but no visible signs of any old house.

It is only one nugget, not two.

Very different on each side. Sorry about the confusion.
 
Some more info...

Iridium is a metallic element that is both hard and brittle. Described as whitish-yellow or silvery in color, it just a little less dense than osmium, which is the densest element22.560 gm/cm3 compared to 22.6 gm/cm3 .

Iridium was discovered by Smithson Tennant, an English chemist, in London, England in 1803, and it's name comes from the Latin for iris, the goddess of the rainbow on account of its colored salts. Tennant was also he discoverer of osmium.

It is found in gravel deposits, and believed to occur only in alloys with other noble metals, i.e., not in an uncombined state. Often it is found alloyed with osmium in compounds called osmiridium and iridiosmium, the origin of the names being obvious. It is, however, extremely scarce, occurring in only .001 ppm in the Earth's crust.
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From: http://www.wisegeek.com/what-is-iridium.htm
 
Here's some more about iridium tipped fountain pens...

What is iridium?
Iridium is a silvery metal of the platinum group, notable for its hardness, resistance to corrosion, and rarity. Naturally-occurring iridium alloys were used for tipping gold dip pen nibs and nibs for older fountain pens. These alloys were unrefined, and could contain as much osmium and ruthenium as iridium.

From the 'teens on, penmakers began experimenting with different tipping alloys, some of which contained little or no iridium at all. These materials were still not fully refined, so nibs predating the 1940s often display considerable variation in the the hardness and homogeneity of their tipping material.

It appears that no modern nibs use tipping material containing iridium, even though some are explicitly marked "Iridium Tipped". Regardless of the material's actual composition, "iridium" has become and remains the standard term for the hard material used to tip a nib.

Nibs that have lost their tipping material can be retipped, though for more common nibs it will be considerably cheaper to obtain a complete replacement. A nib that has lost its tipping material may still be usable. Gold is a relatively soft material, but 14K gold is still hard enough to stand up to considerable wear. This is especially the case if the tip is fairly broad and the writer is not heavy-handed.

For more, see these articles by John Mottishaw
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From: http://www.vintagepens.com/FAQbasics/iridium.shtml

Not melted pen nibs as no other alloyed metals in the piece.
 
I recall from a basic geology course a long time ago that most if not all the iridium on Earth is thought to have arrived when a large asteroid impacted in the Gulf of Mexico and Yucatan Peninsula area. The asteroid came down from an easterly direction.

Most of the discovered iridium has been found in the direct impact area and the 'splash' of debris to the west of the Gulf after impact. It was a strong impact at high speed, a lot of the splash has travelled thousands of miles before coming back to Earth.

Given that this occurred 66 million years ago rather than hundreds of millions or billions of years ago, it not inconceivable that splash from the impact would be found in mixed alluvial sediment rather than in sedented rock.

I went looking and as much as I hate using wikipedia this is a good summary:

http://en.wikipedia.org/wiki/Chicxulub_crater

It says in that wiki article that Iridium averages 670 parts per billion in asteroids, and about 0.04 parts per billion in the Earths crust. So more than likely, you're holding in your hands a chunk of extra-terrestria. Which I think is exciting :)
 
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