Inspired by the top of a Phillips screw,
Handmade machine parts.
Solid Silver! the head and the post are made of solid silver.
First pic : Left brushed , right polished
If you need only a single, you can buy a mixed pair of any of the studs here:
Mixed Pair of G Studs
Screw Earrings-Phillips-עגיל בורג-עגיל פיליפס