Engraving on leather requires a strong and precise laser beam.
Laser engraving works best for lighter color leather.
You can choose to leave as is (black) or paint gold (not always an option).
The picture above is a sample of glossy black leather engraved (font used is Monotype Corsiva). As the laser beam burns the surface of the leather it creates a contrast between the glossy black leather and its burned parts. One may need to hold the item by a light or move it around a bit to fully see the engraving. Subtle, but beautiful.
The engraving below are more contrasted since the color of the leather is not black:
The picture above shows the engraving of a logo on dark brown leather.