Sphalerite

Sphalerite is a natural resource in Astroneer. It has the appearance of dark purple geodes with spiky crystals.

Source
Sphalerite can be found on the following planets:

The gives 2 Sphalerite for every, up to 8 total for 4.

Uses
Sphalerite is used to craft the following items:

Media
Сфалерит Sphalérite Zinkblende