💡 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
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 Colored Amethyst
SCA glass is a critical diagnostic tool for cultural resource assessments and archaeological surveys. 💡 If you find purple glass in a
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 US manufacturers switched to selenium , which turns
Around the start of World War I, the supply of manganese (largely imported from Germany) was cut off. US manufacturers switched to selenium , which turns a straw or amber color when exposed to the sun, marking a distinct shift in the archaeological record. 3. Common Artifact Types Archaeologists frequently recover SCA in the form of:
Beverage and medicine bottles are the most common finds. Tableware: Pressed glass dishes and decorative items.
Found in the ruins of late-Victorian and early-20th-century structures.