Vesuvianites from contact deposits in the Oslo Region are found to contain B₂O₃ in concentrations ranging from about 0.05% to more than 2%. The great variations in the B-contents are believed to be in support of the present view that the boron found in these deposits originates mainly from the sediments, not from the magmas. Some vesuvianites from localities outside the Oslo Region are practically B-free. All examined vesuvianites which contain B₂O₃ notably in excess of 0.5% are optically positive, the others negative.