Author Topic: Is this coin authentic?  (Read 2733 times)

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Offline Karavia

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Is this coin authentic?
« on: February 25, 2014, 02:04:40 AM »
After purchasing this coin, the seller offered another virtually identical coin which caused me to question the authenticity of them both. Looking closely there is a peculiar characteristic - there are numerous small nodules on the surface, including bumps in the punch marks. Does anyone have any insight into this coin's features, or into how to detect counterfeit Mughal dynasty coins in general? The images with dots indicate the location of the nodules. There is one close up image as well.

Thanks very much, Peter








Offline Figleaf

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Re: Is this coin authentic?
« Reply #1 on: February 25, 2014, 12:08:02 PM »
It is difficult to say from this picture. The dealer may have received a number of these coins found together as a treasure. In such a case, some may even be die-identical. One explanation for the bumps may be a rusty die, that was cleaned from rust, leaving some tiny holes. I find this explanation not convincing, because all the bumps are in the field and none on the letters. Here are some questions:
  • Is the weight acceptable?
  • Is the silver good?
  • Are the characters correct and well-shaped?
  • Did you compare your coin with a known good coin?
  • Is the dealer well known or did he at least give you the right to return your coin?
Answering these questions will help you answer yours. I hope that experts on this site, who have seen this coin before will also give their opinion.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline Coinsforever

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Re: Is this coin authentic?
« Reply #2 on: February 25, 2014, 02:51:56 PM »
AH 987 I guess is the date visible on the coin.

You must post photo of another coin which dealer has offered to compare the year .

It doesn't matter if calligraphy is same or almost same or exactly same .

Two coin can be differentiated by their weights as well as years indicated on them.

Only for gold mohur rare possibility of two identical coins minted from same die. For silver many dies so possibility of identical coins are seldom.


Cheers ;D
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Offline Karavia

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Re: Is this coin authentic?
« Reply #3 on: February 26, 2014, 09:55:47 PM »
I'm not sure if a rusty die would account for the nodules in the test marks.

The weight is 7.4 grams.
Silver seems good.
I don't know if the characters are welll-shaped (I'm a beginner!).
I don't have reference material to compare the coin with.
The dealer begrudgingly would accept the coin back (although shipping it is a significant percent of the cost).

The date looked to me like AH 977.
Below are photos of the second coin being offered. I asked for new photos after I had the first coin in my possession. Note that the strike is exactly the same as the first coin both on obverse and reverse.

It looks like there are some nodules on the second coin that are not on the first. The last photo with red arrows points out a few of these.

Lastly, how could test marks be in exactly the same places on two different coins?

Thanks, Peter






« Last Edit: February 27, 2014, 01:40:31 AM by Karavia »

Offline cmerc

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Re: Is this coin authentic?
« Reply #4 on: February 27, 2014, 04:33:45 AM »
Although I know nothing about these types, two coins with the exact same die positioning, edge nicks, and "test" marks is indeed suspicious. Are you sure the new image is a different coin, and the seller did not just get confused and send pictures of the coin you already bought?  I would expect that even forgeries would have slight differences.  Has forgeries entered the electronic age of rapid prototyping and 3D printers (and thus the unexpected dots)?
Defending this hobby against a disapproving family since 1998.

Offline Karavia

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Re: Is this coin authentic?
« Reply #5 on: March 05, 2014, 08:00:08 PM »
It's a replica.
With some help I have determined that this coin is not authentic.
The most clear indication out of several shown to me is the seam around the edge, characteristic of a cast replica. Here's a photo.
I hope my unlucky purchase turns out to be useful for someone.
All the best,
Peter


Offline capnbirdseye

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Re: Is this coin authentic?
« Reply #6 on: March 05, 2014, 10:20:21 PM »
That seam round the edge is not typical of a cast coin as such but it appears to be two halves soldered together which is rather odd  ???
Vic

Offline davidrj

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Re: Is this coin authentic?
« Reply #7 on: March 05, 2014, 11:18:01 PM »
That seam round the edge is not typical of a cast coin as such but it appears to be two halves soldered together which is rather odd  ???

Electrotype?

http://www.calgarycoin.com/reference/fakes/electro.htm

David

Offline capnbirdseye

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Re: Is this coin authentic?
« Reply #8 on: March 05, 2014, 11:28:44 PM »
Electrotypes??

David

I would think it's an amateur attempt at casting which doesn't require too much preparation as there would be with a complete mould as it's far easier to cast two single sides of a coin & then grind the back smooth & thin enough to solder together.
Vic

Offline Filat

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Re: Is this coin authentic?
« Reply #9 on: March 06, 2014, 04:51:08 AM »
Topic Starter I recommend to given the object to check for the presence soldered tape.
« Last Edit: March 06, 2014, 05:11:52 AM by Filat »
YV

Offline Karavia

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Re: Is this coin authentic?
« Reply #10 on: March 07, 2014, 12:25:51 AM »
Under high magnification I can see what looks like file marks around the edge. I can't detect evidence of soldering tape, but anything that would have been on the edge appears to have been removed. Inside the seam is a gritty looking grey substance.

After reading about the methods of creating replicas/forgeries that David linked to above, I would say that it looks a lot like the pictures of an electrotype, or perhaps another amateur casting method as Vic mentioned.

Very grateful for all your help!
Peter

Offline Filat

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Re: Is this coin authentic?
« Reply #11 on: March 07, 2014, 05:41:23 AM »
YV

Offline Husain Makda

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Re: Is this coin authentic?
« Reply #12 on: March 10, 2014, 07:44:48 AM »
Weight itself is a big tell tale sign. Dealors uses lucrative words like 'Underweight Rupee', Mughal mint standards were very strict till Muhammad Shah so no such errors would be entertained. 
Someone once offered me a Rafiuddarajat Surat mint  3/4 rupee weighing around 7.5 grms. Calligraphy was perfect but on closer inspection a totally new method turned out, the person had filed the edges and hammered it.
This can be done when the planchet is large. And most of the later ruler's half rupees where prepared from a regular Rupee die on a half rupee planchet.
Blessed by the Masters.

Offline Karavia

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Re: Is this coin authentic?
« Reply #13 on: March 10, 2014, 06:57:27 PM »
Mughal mint standards were very strict till Muhammad Shah so no such errors would be entertained.

Thanks Husain Makda.
What should the correct weight be for this coin?

Offline Husain Makda

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Re: Is this coin authentic?
« Reply #14 on: March 10, 2014, 08:00:44 PM »
11.44 gms when struck. And less according to wear.
Blessed by the Masters.