Australian Engineers Badge - Info Required.

[JakobVonBismarck]

Hi Everyone,
Recently I acquired this Australian Engineers badge, I was curious as to what period this item would be dated to. Could it possibly be First World War?

I had great difficulty trying to find one on the internet anywhere so could this possibly be quite a rare badge? What would be the price for such a badge like this?

The condition of the badge is displayed below in the two photos attached.

Any thoughts, information or comments would be greatly appreciated.

Thanks
Jacob