Found in the ruins of late-Victorian and early-20th-century structures.

Manufacturers added manganese oxide to "mask" the natural green or aqua tint caused by iron impurities in the sand used for glassmaking.

The purplish hue is the result of a specific manufacturing process:

When first produced, this glass appeared perfectly clear.

Beverage and medicine bottles are the most common finds. Tableware: Pressed glass dishes and decorative items.

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: