GodsMoney

I suspect some of that is down to the photo quality.
... But I didn't like to say!
😎

I think, looking at pictures, your chain is indeed 14ct gold. The rhombus-shaped stamp 585 is an italian hallmark for small gold jewell with a fineness lower than 750. 
The clasp stamped 270 should be the maker mark, even are missing another alphabetic codes. 
I don't think it is 6ct or yellow brass.
Anyway, an acid test will tell you the truth.

@BackyardBullion is who you are on about 👍

I'm glad you enjoy my channel 😅 even though I've yet ( never will ) start one.
That's @BackyardBullion you are referring to sir,but I agree on your comments ( although I'm keeping the compliments) 😂😂
Yeah I honestly think your coin is all good 👍 
 

Ok cheers guys that's good news then. @James32 that reply cracked me up. Are you BYB James btw? If so I love your channel mate awesome, balanced work. Voice of reason in amongst a lot of noise.
 
If it's not you and you've no idea what I'm on about there's a great YouTube channel called backyard bullion 

Ok cheers guys that's good news then. @James32 that reply cracked me up. Are you BYB James btw? If so I love your channel mate awesome, balanced work. Voice of reason in amongst a lot of noise.
 
If it's not you and you've no idea what I'm on about there's a great YouTube channel called backyard bullion 

All is good. +/-0.01g error on your scale, doing two measurements, can easily generate a 0.07g error in your final result. 
So, you are safe and your coin is genuine.
Would be scary to see 8.50-9.50.
10.43 is very close to 10.50.🤗

I have a few ideas..
1) you're coin is geniune 
2) that is close enough considering the amount of user error in trying to weigh a 1oz coin hanging of a piece of string..in a bowl of water whilst you're brain is screaming "hold it fookin steady "🤣
It's not a complete accurate measurement but you are definitely within range considering the variables. 
Any pics???

Yes I got it's second hand quite cheap, not far off 5oz bullion tbh so as long as it's fine silver I'm still happy to have it. Someone I know that polishes said if Silvo is used sometimes this can happen? Looks quite a lot of damage though for just a basic silver polish to do but who knows 

For this big coin will need a minimum 1000g scale, with a minimum of 0.1g accuracy to do a specific gravity test.
On Amazon can be bought a good one up to £15.

Yes I got it's second hand quite cheap, not far off 5oz bullion tbh so as long as it's fine silver I'm still happy to have it. Someone I know that polishes said if Silvo is used sometimes this can happen? Looks quite a lot of damage though for just a basic silver polish to do but who knows 

That has to be wrong on the apmex site. A 5oz coin has to be a lot larger in diameter. Otherwise, it would be really thick.
I suspect the coin concerned has been handled and maybe badly cleaned.

https://www.powercoin.it/en/royal-canadian-mint/1618-maple-leaf-hologram-5-oz-silver-coin-50-canada-2015.html
Powercoin have the correct specs

For a 5oz coin with a 40mm diameter the thickness should be double 😃 I'm only guessing but I believe apmex has the wrong diameter.