Hello stew,
It seems your candle holder is designed by Monica Backstrom,
Educated at Konstfack, the University College of Arts, Crafts and Design in Stockholm, Monica Backström started working for Kosta Boda after graduation in 1965. In 2003 she became professor at Kalmar University of Design in Pukeberg, Sweden. She is represented at design museums all over the world, including the National Museum in Stockholm, the Röhsska museum in Gothenburg, the Victoria & Albert Museum in London, the Corning Museum of Glass, the CooperHewitt Museum and the American Craft Museum in New York.
I found a couple similar to yours in light blue and it was made also in brown ( described as coming from the Tonga collection )
this is the description of the blue piece:
Kosta Boda painted glass votive candle holder designed by Monica Backstrom.
The clear glass bowl shape votive with a candle socket at the center and painted with a white stripe over a dark blue strip over a light blue strip with a sunburst shape spiral through the lines. Initialed in paint MB/ SED on one ray and with a Kosta Boda label.
I Hope this helps.