Heart Shaped Plume Agate Necklace - Natural Designer GemstoneThis unusually beautiful gemstone is a Plume Agate from the USA. This type of plume agate is found in the Owyhee Mountains between Oregon and Idaho. It's valued for its delicate patterns resembling speckled points or floating plumes on a translucent background. Plume agate is a type of chalcedony that forms in hot springs, where microscopic organisms called thermophiles and extremophiles collect silica and other particles to create unique patterns