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Why Is Antique Glass Yellow?

It is easy to assume that just like a well loved book, antique glass acquires a yellow patina over time. On the contrary, yellow was often the intended color at the time of production. Several processes were used to produce yellow glass.

Uses
- Yellow glass is found in costume jewelry, tableware and lighting. Glass beads can be differentiated from plastic or semi-precious gems by feel, as glass is noticeably colder to the touch.
Vaseline Glass
- Under black light, the glass does not appear to be green.
  
  Colloquially referred to as Vaseline glass for its slightly transparent quality, yellow glass with a slight green cast contains two percent uranium dioxide. The uranium fluoresces green when exposed to black light. Vaseline glass appears darker in photos when a flash is used.
Amber Glass
- Amber glass ranges from bottle brown to a light caramel yellow.
  
  Yellow glass with a brown rather than green undertone is commonly referred to as amber glass. This color is created by combining one percent silica from fly ash with a soda-lime mixture. Hues range from bottle brown to caramel yellow.
Obsolescence
- Uranium was used in the war effort.
  
  Production of Vaseline glass was curtailed in the 1940s when uranium use was relegated to the war effort.
Safety
- Some people are cautious about Vaseline glass.
  
  In 1959, production continued, as depleted uranium replaced active uranium. While there are publicly perceived health concerns concerning uranium-leaching, amber glass possesses no toxicity.

Antiques