Blue/grey Australorp or Sapphire Gem, how to tell which?

[chooki]

I have a grey chicken that I have bought from a large mixed batch. The seller said there were Australorp, Isa Brown and a few other breeds.

This is her around 1 year old:

At first I thought that she was a blue/grey Australorp, but then I have discovered that she has yellow soles. The rooster that I have got from the same batch looks like a barred rock mix:

This was her when she was 4 weeks old:

Is there a way to tell Blue/grey Australorp apart from Sapphire Gem? Are there any characteristics that I should be looking out for?

 

[JedJackson]

Yellow soles of the feet indicate a yellow skinned bird, which fits for Sapphire Gem but not Australorp, which are white skinned. So it is likely to be a Sapphire Gem.

The rooster is blue barred, and that is also right for Sapphire Gem males. He could also be a mix if he came from a backyard flock.