Cobalt blue Glass Cube

[Palmetto]

Also posted this in the Todays Finds Forum
This is my first post although I have been on this forum for quite some time-enjoy looking at all the great finds and appreciate the knowlege on this site.
This is an unusual find and I am wondering if any of you think it is old or not. I found it while looking at some new survey lines we had done and was not out treasure hunting at all, but my eyes are always toward the ground.
It was found in the sandy part of a dry run and that run is located about 30 yards below a known old road bed (approx 1900). 1/2 of the glass was sticking out and I thought it was an old bottle.
Turns out it is a solid, cobalt blue glass cube. It measures 1.5 inches cubed and does not appear to have any machine marks on it. Will try and resize some photos but the one pic I am attaching shows the cube as well as the face that has some faded dimple-like patterns on it.
Appreciate any help or info. Thanks.

[GlassyEyed]

That is the way glass cullet was transported on the RR? I've found several large "marbles" on the tracks after they've fallen out of the cars.....

Don't know for sure, but it's pretty cool.

[Skrimpy]

...it's pretty cool.

I don't know what the heck it is, but I concur with GlassyEyed, it's cool. It's at least a neat paper weight.