How do I get a retweet url that proves I retweeted something?

Here is what I am doing using the Android facebook app:
1. Click link in airdrop form to get to the ATFS Labs twitter home
2. Click retweet icon at bottom of pinned post. The icon changes color and also a banner now appears above the post that informs me that "You retweeted this post"

Exactly how do I get the url that proves I retweeted something? The "Copy Link to Post" feature just copies a link to the original post. Also the link it copies is the same both before and after I retweet it or if I undo my retweet.

Please provide an example if this is possible of both the original tweet url and of your RT url.

Thanks!