How do you date a glass bottle?

There are three keys to help with dating most bottles: Side seams: None: bottle may be free blown, in which case it has a very uneven shape and dates before 1860. Or the bottle may have a nice even shape, but was spun in the mold to smooth out the seams; a practice common around 1900-1920.

When did glass bottles have seams?

The concept is that the higher the side mold seam on the bottle the later it was made - at least in the era from the early to mid 19th century until the first few decades of the 20th century.

How can you tell if a glass is pressed?

The tell-tale sign of pressed glass is the seam where the glass was pressed together. A mark on the glass such as an impressed mark, lozenge, diamond, trade or makers marks, or registration number can tell you the date that your piece of glass was made.

How can you tell if a glass is Amberina?

The glass varies in colour from red to amber. Glass which is shaded in colours from blue to amber is known as Blue Amberina or Bluerina. Amberina is made of an amber glass containing some gold. Its distinct colouring develops with applied reheating and cooling.