The color of a bottle not only tells about its value but also about its age. Generally, bottles of rare colors like teal, amethyst, yellow, etc are more valuable than clear, amber, and black ones. Knowing a little about the history of colored glass can help you get a rough estimate of when your bottle was made. For example, the amber color was introduced in glass bottles in the 19th century, so if your bottle is amber, you can be sure it wasn’t created before the 19th century. Similarly, completely clear bottles were first introduced in 1662.