Was Dioskourides a lapidary?
Let's think step by step below.
yes
A lapidary is a person or machine who cuts gemstones; classically, it refers to a person who engraves gemstones.

Dioskourides put his signature on a Roman amethyst ringstone with a portrait of Demosthenes circa late 1st century BC.

Artists sign their work.

.

The answer: yes