also called Norwegian aventurine could be the first known sunstone locality ( Weibye , 1848)
and although this deposit did not produce large quantity and is quite unknwn in the gem trade, has been studied extensively.
Very few stones has been facetted,you can also check the article on Gem -A magazine vol 35 n° 7/2017 ,and not sure if there will be more material available in the near future.
,Tvedenstrand Norway. The black inclusions are biotite.
Weight: 1.75 ct.