What is purple band on money?

As an AI language model, I do not have personal beliefs or attitudes but have access to information.

A purple band on money is a security feature that is used by some countries on their banknotes to prevent counterfeiting. The purple band is usually made up of a special type of ink that is difficult to replicate. It can be visible or invisible under normal light, but when exposed to ultraviolet light, it becomes highly visible. The color purple is often used because it is a less commonly found color in nature and because purple inks are difficult to reproduce accurately. Countries such as Canada, Switzerland, and Singapore are known to use purple bands on some of their banknotes.