Guernsey 1 double 1830

This little copper coin, mintage 1,648,640, is fairly easy to find. It is not expensive (about $5-10), but most samples offered in this price range are in rather poor condition. After purchasing several specimens I have realized that some of them are from different dies (which is not unexpected given high mintage number). My analysis is, as far as I know, is the first one, so please take it with a great deal of scepticism! Hope it will be used as a starting point for future studies by collectors who have access to better and more versatile material.

A 'dot before date' variety is included here as Reverse 5. This one is rare and can be expensive in high grade. Another sample image: https://www.numisbids.com/n.php?p=lot&sid=714&lot=50.

Obverse side is one with a Guernsey shield, reverse side is one with a date.

Obverse dies

Obverse die variations are surprisingly hard to detect. I had to compare images by overlaying them in graphics editor, otherwise they are indistinguishable from each other. This needs more work and more samples!

	Obverse A. Seems to be most common.
	Obverse B. Noticeable ghosting on all three "E"s.
	Obverse C.
	Obverse D. "GUERNESEY" is ghosted.
	Obverse E.

Reverse dies

There are several points of identification. Examine the relative position of letters L and E, distance between L and E, outline of upper digit 1. All differences are small and have to be checked at high magnification.

	Reverse 1. Base of E is strictly level with base of L. Outline of upper digit 1 is regular. Top of the lower 1 is slightly sloping.
	Reverse 2. Base of E is noticeably higher than base of L. Outline of upper digit 1 is irregular below top serif. Top of the lower 1 is flat, no slope at all.
	Reverse 3. There's a miniscule dot before date. The dot is very, very small; open high-resolution photo to see it. It is not a defect; I have two coins with this reverse. Base of E is level with base of L. E is closer to L than in reverse 1. Outline of upper digit 1 is regular. Top of the lower 1 is slightly sloping.
	Reverse 4. Base of E is a little higher than base of L. L is slightly further from E than in reverse 2. Zero is clearly higher than rest of date figures. Upper digit 1 is poorly engraved under top serif. Top of the lower 1 is flat, no slope at all.
	Reverse 5. Large dot before date (E1A in Exley catalogue). The dot is large and aligned nearly with bottom of date. Base of E is almost level with base of L. Outline of upper digit 1 is regular. Top of the lower 1 is slightly sloping.
	Reverse 6. Base of E is almost level with base of L (slightly higher). Outline of upper digit 1 is regular. Top of the lower 1 is slightly sloping. This one is similar to reverse 1, but word DOUBLE is longer in reverse 1.

Coins from my collection

I have nineteen samples and hope to acquire more in the future.

sample a: reverse 1 + obverse A

sample b: reverse 3 + obverse C

sample c: reverse 2 + obverse ?

sample d: reverse 2 + obverse C

sample e: reverse 1 + obverse C

sample f: reverse 1 + obverse C

sample g: reverse 4 + obverse A

sample h: reverse 5 + obverse ? (similar to obv. B)

sample i: reverse 6 + obverse B

sample j: reverse 4 + obverse ?

sample k: reverse 4 + obverse A

sample l: reverse 6 + obverse D

sample m: reverse 6 + obverse A

sample n: reverse 6 + obverse B

sample o: reverse ? + obverse A

sample p: reverse 1 + obverse A

sample q: reverse 6 + obverse A

sample r: reverse 6 + obverse A

sample s: reverse 3 + obverse C

sample t: reverse 4 + obverse E

sample u: reverse 2 + obverse E