This is a heavy square vase (or is it a votive?) 7,5 x 7,5 cm (3"), height 8 cm with a design of prisms and diamonds. The bottom is ground and polished. There is a circular indent diam 4cm in the bottom so maybe this is an upside down candle stick for large candles?
It looks like Ruda or Hellsten or Aladin. Does anyone recognise it?