NRF52840 evaluation board with a battery charger (BQ24072), display(Adafruit 1.47" 172x320 ST7789), and a trackball sensor (PAT9130)

4 Pin crystal, GND on pins 2 and 4

An xtal electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency.