MATCH, FIND & Conditional Formatting

Hi:

I would like to use a function that checks an entire range A2:A100 and if it finds any duplicate TEXT items (like two or more different cells that contain "Open" in that range) - I want to show the duplicate item found in cell A1 or it can highlight all the cells that are duplicate with a different color.

Thank you!

p.s., I want to disregard blank cells in the search for duplicate items.