What color of Jade or Tian Lu Pixiu becomes the means of good luck?

I hope someone here knows what Pixiu or lu Tian. I just want know what color changes mean that good and bad colors mean? is that it becomes a darker green is good or lighter and more transparent? how to clean it? BTW mine is a pocket format.

Try Google to this information.

[affmage source="ebay" results="90"]Tian Jade[/affmage]