# Reviewing the Gem UV-Tracking Necklace for Health and Sun Exposure A wearable device that tracks UVA and UVB radiation to monitor skin health. - **Source:** [The Verge (theverge.com)](https://www.theverge.com) - **Published:** 2026-11-07 - **Topic:** [technology](https://brifing.si/c/technology) - **Original article:** - **On Brifing:** https://brifing.si/s/8d5d02bf-1eca-462f-bb99-866ff7b68889 ## Personalized UV Monitoring Device The Gem is a $249 wearable necklace designed to track individual UVA and UVB radiation exposure. Unlike generic weather forecasts, this titanium-finished pendant measures specific light metrics. It aims to help users balance the potential health benefits of sunlight, such as vitamin D production, against the risks of skin damage. ## Hidden Dangers of Shade During an outdoor party in Los Angeles, the author experienced heat exhaustion despite sitting under a patio umbrella. The Gem alerted her that UV radiation was still significant due to environmental scattering and reflection. This incident highlighted that shade does not provide complete protection from UV rays or heat-related health risks. ## Technical Capabilities and Design The device features a sensor that differentiates between UVA and UVB radiation, providing data through a companion app. It boasts a one-week battery life and a discreet, jewelry-like aesthetic. The manufacturer, The90, plans to expand the ecosystem with accessories like hat clips and bag tags for users who prefer non-necklace options. ## App-Driven Health Insights The mobile app processes sensor data to offer insights into skin aging risks, vitamin D production, and sunburn countdowns. Users can input personal profiles, including skin type and sunscreen usage, to receive tailored advice. However, the app must remain active in the background on iPhones to ensure continuous, accurate data tracking. ## Balancing Sunlight Exposure The app uses a 'Sun Score' to help users find an optimal balance of sun exposure. The author discovered that her daily habits often fluctuated between extremes, either getting too little sunlight for vitamin D or risking overexposure. The device shifted her focus from aesthetic concerns to overall physiological well-being. ## Accuracy and Software Limitations While the sensor readings appeared responsive to environmental changes, the app's predictive countdowns for vitamin D and sunburn showed significant fluctuations. These estimates often changed dramatically within minutes, making them less reliable for precise planning. The author ultimately relied on the broader trends rather than the specific time-based countdown features provided. ## Medication and Heat Sensitivity Using the Gem prompted the author to investigate her own health, leading to the discovery that a medication she takes increases heat sensitivity. This realization helped explain recurring episodes of feeling unwell during outdoor activities. The device served as a catalyst for better self-awareness regarding environmental triggers and personal health limitations. ## Value and Final Verdict At a $249 price point without a subscription, the Gem is a premium investment for those spending significant time outdoors. While it lacks perfect app integration, it successfully encourages mindful sun habits. It moves the conversation beyond vanity-driven skincare toward a more holistic understanding of how sunlight impacts human health. ## Sources covering this story - https://www.theverge.com/tech/1023230/the90-gem-necklace-hands-on-impressions — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._