US — The Verge
The UV-tracking Gem made me rethink how sunlight affects my health, not just my appearance
Devices1 min read
A tech writer tested Gem, a $149 necklace that tracks UV sun exposure and sends alerts to a phone app. She found it changed how she thinks about sunlight and her health, not just her looks.
A UV necklace that changed her view of the sun
Sheena Vasani wore the Gem UV-tracking necklace while at an outdoor party in Los Angeles in August. She sat under a patio umbrella with a fan, but she still felt sick. Her Gem app then warned that her UV exposure had risen a lot. The umbrella had not blocked the UV rays. Later she found that one of her medicines makes her more sensitive to heat, which may explain similar past episodes.
Key facts about the Gem
Why UVA and UVB matter
UVB rays cause sunburn and help the skin make vitamin D. UVA rays add to premature aging, even when skin does not look burned. The Gem's app uses a skin profile, based on factors like skin type, sunscreen, and clothing, to estimate things such as vitamin D production. These are predictions, not direct measurements of how the body reacts to sunlight.
Why this matters
The story shows that shade and fans do not fully protect you from UV rays. Rays can bounce off or scatter around objects, so you can still get exposed. Heat illness and UV exposure are different problems, and it is easy to mix them up. A device like this can help people notice risks they might otherwise ignore.
Glossary
- Gem
- A necklace from The90 that tracks UV sun exposure and shows results in a phone app.
- UVA
- A type of sun ray that contributes to premature skin aging, even without sunburn.
- UVB
- A type of sun ray that causes sunburn and helps the skin make vitamin D.