Fitzroys Stormglass historical weather and storm predicting device How the Storm Glass works is still a mystery, but it is believed that electromagnetic changes in weather patterns activate the crystals inside (sealed glass chamber fill with crystals when air pressure decreases). How to read: A: Clear Liquid Bright and clear weather B: Cloudy Liquid Sometimes with small stars and crystals at the top. Cloudy weather and often predicts thunderstorms and rain. C: Small Stars in Liquid Humid or foggy weather D: Large Flaky Crystals Cloudy skies, snow in winter. E: Threads of Crystals At The Top Winy Weather F: Crystals At The Bottom, Frost may be coming. The Cloud Storm Glass comes with a stand, making it a wonderful gift. Stands 4.3" Tall This is a gorgeous decorative gift idea for the adult who has everything or someone who finds meteorology fascinating.