The present mandala is accompanied with an old inventory sticker; the seal mark may be identified as Ershiqi nian fucha, 515, yin", 'Inspected after the 27th year, 515, silver'.
The seven stepped pyramid represents Mount Meru (also known as Sumeru), the cosmic mountain that is regarded in Indian cosmology as the axis of the universe, and the dwelling place of the gods.
The concept of Mount Meru also exists in Hinduism but in Buddhism, the world is seen as a large disc, cakravala, and contains a series of seven golden mountains and four continents; sentient beings are thought to reside on the Jambu continent and the remaining three are occupied by higher beings, cf. J. Menzies (ed.), Buddha - Radiant Awakening, Art Gallery New South Wales, 2001, p. 69.
The present mandala is a Chinese version modelled after a Tibetan mandala given by a Dalai Lama as a birthday tribute to the Emperor, illustrated in Cultural Relics of Tibetan Buddhism Collected in the Qing Palace, Forbidden City Press, 1992, no. 128. A slightly different interpretation of the same type of mandala is found on two gilt-copper examples; both of these are modelled with the 'four continents' above clouds and surmounted on the platform steps of Mount Meru. The first of these mandala is from the the Palace Museum, Beijing, illustrated op. cit., 1992, no. 127-1; and the other from the National Palace Museum, is illustrated in A Special Exhibition of Buddhist Gilt Votive Objects, p. 92, no. 15. The published examples are modelled with additional insertions at mid-levels along the stepped mountain representing the sun and moon; and in the case of the present mandala, it appears as a separately cast circular disc emerged from a moveable stem.
Compare also a gilt-bronze Meru Mandala from Eastern Tibet, with the stepped pyramid surmounted by a crystal, from the Zimmerman Family collection, illustrated op. cit., New South Wales, 2001, p. 70, no. 49.