Pearlwort is a cushion-forming perennial herb in the Caryophyllaceae family. The species is usually covered in small hairs with glandular tips, has small linear leaves, and small white flowers that occur singly near the ends of its branches.
The stems of the Pearlwort are flexible, stoloniferous and are up to 10 cm long. The leaves are sessile, linear, 2-25 mm long and 0.2-0.5 mm wide. The leaves usually have narrow scarious margins, and a pointed tip that may be short and sharp. The flowers have 4 petals and 4 sepals. The stalk of the flower is erect and 6-12 mm long. The sepals are oblong to elliptic, with a pouched base, 2-2.5 mm long. The scarious margins are often purple-tinged and are more-or-less pressed closely to the ripe fruit. The petals are ovate to suborbicular, white and 2.5-3.5 mm long. The flower has four or eight stamens and four styles. The fruit is an oval shaped capsule 2.5-2.75 mm long and contains numerous dark reddish-brown kidney shaped seeds.