Queen Elizabeth the Queen mother 80th Birthday coin from 1980

I already asked Zacuk but he was none the wiser this time so I'm throwing it out there for a suggestion... I mainly noticed it because of weight...
Diameter : 38.5
Thickness : 3.2
Weight : 30g

​​​Did the magnet test and ping test so definitely not silver... Ideas?
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Hi Anne Lunn, not sure what you are actually asking about this coin? https://en.numista.com/catalogue/pieces5981.html

Sorry... I wanted to know why it is thicker and heavier that the other ones I have?
My first thought was different material, my second was a fake... But both seem wrong from the tests I have done.
Was wondering if anybody had any other ideas?
Thank you

The diameter and thickness appear to be within tolerance margins (note that in the Comments of link provided that 'Planchet thickness The coin thickness measures 2.9 mm at the centre and 3.2 mm at the rim' (not sure either what you used to take these measurements).

In regards to weight I was going to say that maybe your scales need re-calibrating but after reading your reply it appears that you have others to compare it with ... but then again, if you allow a tolerance margin of 5%, then the weight is not far off 28.28 g.

Hi... I used a digital caliper, digital scales and used neodymium magnets to double check if the material was different to the others (did the slide test). I followed every test I could find. Even downloading the app for the ping test to double check results....
I noticed the thickness ref in the coin listing so wasn't too worried as its within parameters. But would of expected maybe in the region of 29g.. But 30g was higher especially as there is no difference in wear between my other coins... All are UNC and some untouched in cases....
Sorry if it seems like a lot of going on for something so small but I get a bit like a dog with a bone when it comes to my coins especially if something is slightly off.. ☺️