Manganese glass is the type of glass that glows a distinctive purple or violet hue when exposed to ultraviolet (UV) light.
Understanding Manganese Glass and Its Purple Glow
The unique luminescence of manganese glass is attributed to the presence of manganese oxide within its composition. When this type of glass is illuminated by ultraviolet light, particularly at a wavelength around 365 nanometers (nm), the manganese atoms absorb the UV energy. This absorbed energy then causes the electrons within the manganese to reach a higher energy state. As these electrons return to their stable state, they re-emit the energy as visible light, resulting in the characteristic purple or violet glow. This phenomenon is known as fluorescence.
Historically, manganese was often incorporated into glass formulations for various reasons, including acting as a decolorizer to counteract the greenish tint caused by iron impurities.
Identifying Manganese Glass
Identifying manganese glass primarily relies on its reaction to UV light. Here are key indicators:
- UV Light Test: The most definitive way to confirm manganese glass is to shine a UV blacklight (ideally one that emits light at 365nm, which is optimal for manganese fluorescence) onto the object in a darkened room. If it contains manganese, it will exhibit a bright purple or deep violet glow.
- Appearance in Visible Light: Without UV exposure, manganese glass typically appears clear. It may sometimes have a very subtle yellowish, brownish, or even faint pink tint. It does not naturally appear purple unless it has undergone prolonged exposure to sunlight (solarization), which can permanently alter its color over time, but this is distinct from its fluorescent glow.
- Historical Context: Manganese was a common additive in glass produced from the mid-19th century through the early 20th century, so older clear glass items are more likely to contain it.
Distinguishing from Other UV-Reactive Glass
While manganese glass glows purple, it's important to differentiate it from other types of glass that also react to UV light with different colors. Each type's glow is due to specific activating elements:
| Glass Type | Primary Activating Agent | Glow Color (under UV) | Common Appearance (visible light) |
|---|---|---|---|
| Manganese Glass | Manganese | Purple / Violet | Clear, yellowish, or faintly brown |
| Uranium Glass | Uranium | Bright Green | Greenish-yellow |
| Selenium Glass | Selenium | Pink / Orange | Orange, red, or pink |
| Cadmium Glass | Cadmium | Orange / Red | Yellow or orange |
In summary, if you're looking for glass that radiates a captivating purple under a blacklight, manganese glass is the type you're seeking.
