Blumenstein is a municipality in the administrative district of Thun, in the canton of Bern in Switzerland. Blumenstein is first mentioned in 130…Blumenstein is a municipality in the administrative district of Thun, in the canton of Bern in Switzerland. Blumenstein is first mentioned in 1305 as Bluomenstein. Tannenbühl, which became Outer-Blumenstein in 1859, was first mentioned in 1316 as Tannenbuel.