This achievement is easiest to get when starting the game fresh for the first time (you'll understand why in a minute). To get the the secret gyro area in the clouds, you must start any level with a 7 in the 10,000's column of your money total (so for example, 70,000, 1,072,534, etc). It doesn't matter WHAT you money total is, you just need to make sure that when you start a level, you have a 7 in the 10,000's digit.
You can do this on any level, but I found it was easiest to do it on the Amazon level, on your first run through of the game. This is because you have a clean slate, and you can make sure you have the right money total by only picking up certain gems on the the Vault tutorial level.
If you already have money, or you far surpassed this during your first run through of the Vault, you can also buy a painting so that your money total is diminished to the point that you have a 7 in the 10,000's digit column.
After you start up a level with a 7 in the 10,000's column, you will get to a secret area where Gyro drops gems. The achievement will pop as soon as you get to the cloud area. It doesn't matter if you die right away (although it's good if you don't because it's a source of extra money), you will still get the achievement regardless.