Ornithogalum conicum is a half-hardy, deciduous, winter-growing, bulbous plant, 350–600(–900) mm tall. The bulb is nearly globose, 25–45 mm in diameter, with whitish, papery outer tunics. It has a basal rosette of leaves that are oblong to lanceolate, spreading or suberect, and with entire margins, with a dense fringe of slender hairs. The leaves are 45–100(–120) mm long and 6–25(–30) mm broad and are one-third to one-quarter as long as the flowering stem. The plants grow during the rainy winter months, and the leaves wither in spring (Sep. –Oct.) so that the leaves are partially or completely dry at flowering. Each bulb produces a raceme of 15–30, star-shaped, shiny white flowers, tinted greenish yellow in the centre, in early summer (Nov. –Dec.). The flowers are unscented to faintly honey-scented. The raceme is compact, conical to cylindrical in shape, and 30–80 mm long, elongating to 60–100 mm long in fruit. The ovary is greenish yellow to bright yellow and the anthers are yellow. The 2–3 mm long seeds, are produced in loculicidal capsules (splitting lengthwise).

Ornithogalum conicum is very similar to the ‘true’ chincherinchee, O. thyrsoides, but the latter differs in having smooth-, not hairy-margined leaves and smaller bulbs (seldom more than 20 mm in diameter). O. conicum flowers are pure white, the sepals acuminate, spreading, but never curled back as in O. thyrsoides. Also, the flowers of O. thyrsoides often have a dark centre, whereas those of O. conicum never do. Both these species flower in early summer, from November to December, although O. thyrsoides generally flowers earlier (Sep. –Oct.) than O. conicum (Nov. –Dec.). O. conicum can also be confused with a white-flowered form of O. dubium on Table Mountain, but O. dubium differs having a smaller bulb that has dark tunics, and the ovary in the centre of the flower is usually blackish, where O. conicum has a yellow ovary.