You grant darkvision up to 120 ft. to creatures inside of a 15ft. amethyst prism, for a duration of 10 minutes. If cast as a ritual, either with ritual caster feat, wizard subclass or book of ancient secrets invocation, the spell lasts for 8 hours.

In addition the creatures can see through magical darkness, they have advantage to their perception and investigation checks that rely on sight and advantage on initiative checks.

The darkvision makes them see in shades of purple even if there are light sources around.