This is a small perennial herb producing a slender to threadlike stem just a few centimetres long, growing decumbent or erect.

The alpine pearlwort is a small, tufted perennial plant growing from 3 to 10 centimetres (1.2 to 3.9 in) tall.

Its stems are semi-erect and the stalked leaves are in opposite fused pairs with slender linear blades, entire margins and blunt tips.

It is found in short turf in thin soils on fell tundra, under snowdrifts, in melt-water wetlands, on ledges on rock faces, rocky banks, meagre pastures, roadside banks and bare ground.

During the winter its dwarf stature and covering of snow protect it from the worst of the winds and low temperatures.