Can anyone identify an antique?

I was looking at a teapot we've had for a long time that came with our house when I was a baby. it's silver-colored, and my mom says it's stainless steel, but she might be wrong...it's handle is black plastic, and the top is hinged on. It has a decorative piece of gl on top. it isn't in the best condition, so I didn't think it was worth much. On the spout, it says "pat. Dec. 28. 1915", but there's no company name I can find. does anyone have an idea, or know how I can find out what company made this, and if it's worth anything? there are 2 cracks on the gl part, and it looks knicked up, but since it's made of metal I figured all it needed was good cleaning and polishing and the like. Thank you for reading <3