It has that faceted look of a glass bead, which would make it historic or modern. There are also some agate beads which are faceted, also historic to modern in your area. Neat find, either way. A plastic or resin bead is also another option which would put it into the 1900's or later.
Amber is surprisingly light. Both amber and plastic and would be warm to the touch compared to glass/agate. Sounds strange, but if you touch it to your lips you should be able to tell if it's warm or cold. Another test is that amber will sink in fresh water and float in salt water, glass should sink in both, and plastic will either float or sink in both.
If you do the water test, make sure to rinse it off when done.