Info at http://en.wikipedia.org/wiki/Tibet
http://en.wikipedia.org/wiki/Tibetan_tangka
Mass=4.1 g
Obverse: Center: Stylized Lotus; Around:
brka-shis rtags-brgyad (the eight auspecious symbols in eight radiating petals; see note below).
Reverse: Center: Eight-petalled wheel (flower) within a star; Around: Tibetan inscription (broken into eight oval frames; starting from top, moving clockwise)
dga'-ldan pho-bran-phyod-las-rnam-rgyal (The Palace of Ga-den is victorious in all directions) (Note: The Ga-Den Palace was the former residence of the Dalai Lamas, located in Drepung Monastery near Lhasa.)
The eight auspecious symbolsThe eight symbols depicted on the coin are:

1. White Parasol/Umbrella of sovereignty
2. Two golden fish of good fortune
3. Treasure vase/Amphora of ambrosia
4. Lotus
5. Right-spiraling White conch shell
6. Endless knot/Emblem of endless birth
7. Banner of victory
8. Golden Wheel/Wheel of Dharma
For details of their significance, see
The Handbook of Tibetan Buddhist symbols By Robert Beer