3-D LASER ETCHED CRYSTAL GLASS CUBE New York City Twin Towers Hologram | eBay
Bob's Watches - What year did Rolex begin micro-etching a tiny crown logo at the 6 o'clock position on the crystal that protects the dial? — More details on BobsWatches.com | Facebook
Oddly filled laser-etched crown logo on crystal of 41mm Submariner Date magnified under microscope (vs. what it's supposed to look like) : r/rolex
Theory: Rolex Serial Number encoded in crystal Laser Etched Crown (LEC) | Replica Watch Info
How to find the laser-etched crown on your Rolex Watch | Bob's Watches - YouTube
Horological Meandering - The Hard to Find Logo That Can Help Check the Authenticity of Your Rolex Watch Crystal