Elaeocarpus angustifolius is a rainforest tree in the Elaeocarpaceae family, bearing bitter edible fruit. It is commonly known as blue marble tree, and also as blue fig or blue quandong, although it is not closely related to figs. The junior synonym Elaeocarpus grandis, from a later description of the species by Ferdinand von Mueller, is also frequently found. A large tree up to 50 metres tall, usually with elaborate buttressed roots.
It is found in the eastern Australian States Queensland and New South Wales and New Caledonia.
The fruit of this species is round and blue, between 20 and 30 mm across, and has a seed with deep convolutions in its shell. These are eaten whole by cassowaries, woompoo pigeon and spectacled flying foxes, which pass the nut undamaged.
The species is well regarded for its timber and as a key in regenerating rainforest. The seeds are used in Hinduism as prayer beads by the name Rudraksha.