Amethyst glass dating

Amethyst glass dating

The bottle pictured to the left above would be referred to as a medium cobalt blue. It was also reputedly hard on the longevity of glass melting tanks and pots so was avoided by some glass factories. This colorless glass will variably turn amethyst upon long term exposure to sunlight. The quart beer bottle to the left is a typical medium amber color - not too dark and not too light.

True red colored utilitarian bottles are very unusual and usually referred to as ruby red. Thus, there is some diagnostic bottle typing and aging utility with these colors based on empirical observations. For example, the fruit jar pictured below would be considered deep blue aqua.

These faint colors are viewed easiest when looking through the thickest portion of the bottle, i. This bottle is of very thick glass so that it is quite black even when backlit.

Different colors and shades of green can be found in just about any type or age of bottle providing no easily described diagnostic utility to this category of colors. This color difference would only be evident with much experience looking at such bottles and is not absolute.

This early American NewHigh levels of iron

These olive colors vary widely and grade into the other greens noted above as well as the amber colors which are discussed next. Forest green is a color variation that seems to be most commonly found in early American made bottles and flasks with a color that is shifted more towards the green than the olive.

This early American New England flask has an eagle motif on one side, a Masonic emblem on the reverse, and was produced ca. High levels of iron produce darker greens, black glass, and even amber. An interesting aspect of some milk glass is that it was made with manganese dioxide in the glass batch. It is an example showing where the olive color begins shifting towards amber colors.