Gypsum Flowers
Gypsum flowers are fascinating speleothems—cave formations—characterized by their crystal petals that radiate outward from a central point. The petals are either fibrous or prismatic crystals growing parallel to each other, and are usually composed of sulfate minerals like gypsum or epsomite. But in rare occasions can also form from halite or even ice!
Unlike stalactites that grow from the tip, gypsum flowers grow from the base and may actually carry parts of the cave wall with them! This can actually contribute to the breakdown of cave walls over time. Their formation occurs under relatively dry conditions through the local feeding of mineral solutions through pores in the rock under capillary pressure. And the curvature of the “flower petals” is affected by changes in the flow rate of these solutions, which in the case of gypsum, is calcium sulfate.
Selenite, a variety of gypsum, is also able to form into shapes resembling flowers, known as gypsum flowers, which are curved rosettes of fibrous gypsum crystals found in solution caves. These crystals can exhibit various colors and are typically transparent to translucent, which contributes to their vibrant appearance. The unique shapes and structures of gypsum flowers are a result of the mineral’s specific growth patterns, often resulting in delicate and intricate formations.
For more detailed exploration of these captivating natural formations, the National Speleological Society provides extensive information and imagery showcasing the variety and beauty of gypsum flowers.
All images credited to: James St. John/cc
