Extra Gem When Socketting

Okay, so I was socketting my gems into my Scale Leggings of the Skirmisher ( Scale Leggings of the Skirmisher - Item - World of Warcraft ) and I had 3 gems, Delicate Cardinal Ruby ( Delicate Cardinal Ruby - Item - World of Warcraft )

I discovered this on accident, but I remember EXACTLY what I did.

What I did:
Firstly, I put my gems into a socket. I realized they were stacked in a stack of 3, so I took them out.

Next, I took 1 gem out of the stack and put it inside of the pants. I then split the other stack of 2 in half and put one gem into it.

Then I noticed that all 3 gems were already in the pants (This is the part that really confused me) and I also had one extra gem in my bag.

I went ahead and did the socketting, and I still had the 1 gem in my bag, and I had all 3 gems socketted into my pants.

After a couple of tests, I found out a method.

Method:

1. Start with a stack of 2 and a stack of 1. Put one gem inside of the item's socket
2. Split the other stack (the stack of 2)
3. You now have 4 gems. Three in your bag and one inside of the item's sockets. If you take the gems out of the item's socket, you will have 3 once again. So basically, you just get an extra free gem when you socket the gems.