Saru's Kelpien knife
A Kelpien knife was a horticultural tool used by the Kelpiens on Kaminar.
On the day that Saru planned to leave Kaminar, he claimed to his sister Siranna that he wished to stay out to watch the stars. She gave him her knife, for night-blooming flowers. This was the only keepsake that Saru took with him when he departed with Philippa Georgiou. (ST: "The Brightest Star"; DIS: "An Obol for Charon")
Saru used the knife to trim the flowers he kept in his quarters on USS Discovery. In 2257, he asked Michael Burnham to sever his threat ganglia with it, so as to release him from the suffering of vahar'ai. (DIS: "An Obol for Charon")