Barn stars are a type of decoration that are believed to bring good luck and ward off evil spirits. Early Dutch and German settlers in Pennsylvania commonly installed barn stars on barns to protect them from evil spirits and to bring good luck to farmers. A brown star is known to symbolize friendship and strength, while white stands for purity and energy. A violet star is considered holy, while a green star symbolizes hope for growth and fertility on the farm. If you see a blue or black star, they symbolize protection for the farm.