Mini
A first light for young collectors (adult supervision recommended), with onboard charging.
- Wavelength
- 365 nm
- Power
- Onboard charging
- Price
- $23
- Home
- Fluorescent & UV
Fluorescent & UV
Fluorescent minerals and UV flashlights
Quick answer
Fluorescent minerals glow in visible colors when ultraviolet light hits them: they absorb the invisible UV and give it back as visible light. Longwave UV (about 365 nm) makes some minerals glow, while shortwave UV (about 254 nm) brings out different, often brighter colors in others. Some minerals respond only to longwave UV light, while others respond only to shortwave, and others to both, showing different colors.
See the difference
What does a fluorescent mineral look like?
In daylight many of them look plain. Drag the handle to see the same rock under UV light.
This is one of John's own specimens: a plain, speckled tan rock in daylight, scattered with bright orange spots that glow under UV.
UV LIGHT
DAYLIGHT
Specimen gallery
Tap Daylight or UV to switch the light. More pairs will be added as John photographs them.
Next pair from John:
same specimen, same position,
daylight + UV
same specimen, same position,
daylight + UV
Longwave vs shortwave
What is the difference between longwave and shortwave UV?
They are different wavelengths of ultraviolet light. Some minerals glow under one, some under the other and some under both, often in different colors.
| LW Longwave | SW Shortwave | |
|---|---|---|
| Wavelength | About 365 nm (UVA) | About 254 nm (UVC) |
| What it shows | Many fluorescent minerals respond, such as some fluorite and calcite | Brings out strong colors in minerals such as willemite, scheelite and some calcite |
| Filter | The filter eliminates any ambient purple glow, so the true fluorescent colors are clearly visible. | This filter also acts as the LW filter does. SW UV light is harmful much more quickly than LW UV light. |
| Safety | Don't look into the beam | Can harm eyes and skin quickly. Always wear UV-blocking glasses |
UV flashlights
Which UV flashlight do I need?
Start with longwave if you're new to fluorescent minerals. Add shortwave when you want to see the full range of colors. John carries both, and all of his UV flashlights are rechargeable.
LWLongwave (UVA) · 365 nm
4-watt
Narrower beam than the 6-watt.
- Wavelength
- 365 nm
- Power
- Rechargeable
- Price
- $59
6-watt
Slightly wider beam than the 4-watt.
- Wavelength
- 365 nm
- Power
- Rechargeable
- Price
- $69
Convoy C8
Narrower beam.
- Wavelength
- 365 nm
- Power
- Rechargeable
- Price
- $79
SWShortwave (UVC) · 254 nm
Twist
For the full range of fluorescent colors.
- Wavelength
- 254 nm
- Power
- Rechargeable · charger included
- Price
- $139
All of our UV flashlights are rechargeable. The Mini model uses onboard charging, similar to a cell phone. All of the others come with the needed rechargeable batteries, and a charger is included in the price of the flashlight. Extra batteries can be purchased.
The shortwave beam is drawn green here only to show it; real shortwave light is mostly invisible.
UV safety
- Never look into the beam of any UV light, and never shine it at people or pets.
- Shortwave UV can harm eyes and skin. Wear UV-blocking glasses and keep exposure short.
- Keep shortwave UV flashlights away from children, and supervise young collectors using any UV light.
- Ordinary sunglasses are not enough for shortwave UV. Use glasses rated to block UV.
Hear about the next show first.
A short email before each show, invitations to house shows, and word when something special comes in. Nothing else.