That one looks like baroque akoya pearls. They are less durable because breakage can occur at the little flattened ends of the pearls. Examine them closely to see if there is already any pearl that has broken or chipped nacre near the drill hole.
Akoya pearls have a bead inside. The baroque ones may have thinner and thicker areas of nacre. Where it is thinner, nacre can chip off. They can be very lustrous though, and suitable for occasional wear.