Help identifying a small coin

[bongobill]

Having only ever bought Sovereigns and Britannia's from larger dealers before my experience with gold coins is limited. However I was given a gift recently (by somebody with absolutely no knowledge of precious metals and informed me it was an ebay buy) which I think may be some kind of commemorative coin of some sort, but I have no idea who minted it if it is some private mint or if it is even an 'official' government mint. From what I gather it is supposed to be a Tristan da Cunha one crown, hence the TDC. All my google searches have come up with very little and at most I have found what seems to be a half crown version with any sort of info on the specifications of it. I was just wondering if any more knowledgeable folks might have a clue to what the specs of this actually are as I haven't a clue (Plus I don't have anything here to check weight or purity at home) and would like to know if it is actually worth anything more than its scrap value.  Any help would be greatly appreciated.

Specs for half crown.. I assume perhaps the one crown version is double the content being a 1g coin.

Tristan da Cunha 1/2 Crown Minigoldmünze, 0,5 g Gold 2013
Grade: Proof with capsule | Abbreviations
Material: Gold
Weight: 0.50 g 
Fineness: 999.9 ‰ (0.50 g fine) 
Diameter: 11.00 mm
50th Anniversary of the Coronation of Queen Elizabeth II.

 

Pic of one side the one crown (as I don't have the actual coin to hand atm)

[Kman]

I know I've seen that portrait of Liz before 

My guess is it's from The London Mint Office or Jubilee Mint 

I think it's most likely a medal rather than a coin and might not be 24c, possibly 14c

^ Could be totally wrong, just guessing, I'm sure someone will correct me if so 

[Murph]

The queen looks rather manly in the picture of the obverse, the chin and lips are rather proud but it might just be the photo.

I'd have thought the crown would be the same purity as the half but would have guessed at around 14kt if you hadn't shown me the half crown specs.

[Murph]

Why would a 50th anniversary of the queen's coronation coin be dated 2013 anyway?

[bongobill]

It has 60th on the one I have, I assume it says 60th on the smaller one too, but it's hard to make out in that picture for sure, must be a typo in the specs.