: A dark bluish gray splat gear with 10 teeth used in various Technic and specialized sets.

If you are looking for a physical part rather than a video, the sequence "3543" or "23543" matches several industrial and automotive components: Automotive & Industrial Parts

The reference appears to be a specific video file hosted by Nexus Gems, showcasing a 4.82 Ct Natural Ethiopian Faceted Opal . This multi-color "Welo Rainbow Opal" is often listed on platforms like Etsy as a loose gemstone for jewelry.