Glass that has turned lavender with age has manganese in it and makes it a little easier to date. Glass in its raw state is pale green. To make it white or clear a bleaching agent was used. But when WWI broke out, this was no longer the case.
It is now possible to purposely "sun-purple" pieces to give them an antique look. However, with a paperweight, I sincerely believe this was not the case. It was probably on a desk, near a window for several decades. Also, it has a seam in the glass so it is not antique, but is still vintage.
Weight: 13 1/2 oz Dimensions: 2 inches tall X 3 1/4 wide.