Because manganese was the primary decolorizer used specifically from 1890 to 1920 , the presence of SCA shards helps researchers pinpoint the age of a historical site.
This report examines glass, a specific type of historic artifact frequently used by archaeologists to date sites from the late 19th and early 20th centuries. Executive Summary
Beverage and medicine bottles are the most common finds. Tableware: Pressed glass dishes and decorative items. Colored Amethyst
Sun-colored amethyst refers to glass that has turned a purplish tint due to prolonged exposure to ultraviolet (UV) light. This phenomenon is not natural to the glass's original state but is a chemical reaction involving manganese oxide, which was used as a decolorizer in glass production between approximately . 1. Chemical Composition & Origin
The purplish hue is the result of a specific manufacturing process: Tableware: Pressed glass dishes and decorative items
When exposed to sunlight (UV radiation), the manganese undergoes a chemical change, shifting the glass from clear to various shades of amethyst or violet. 2. Archaeological Significance
💡 If you find purple glass in a historical context, it likely dates to the turn of the 20th century and was originally crystal clear before being "sun-colored" by decades of exposure. APPENDIX E: CULTURAL RESOURCE ASSESSMENT this glass appeared perfectly clear.
When first produced, this glass appeared perfectly clear.