This rare and exclusive badar besi mustika stone is obtained from a holy cave in the Brantas River valley at the slopes of Mount Wilis in Kediri, East Java. The area contains several archaeological remains of sacred sites of the ancient Javanese Hindu Kingdom of Kediri (1045–1221 CE). King Airlangga, the founding father of the Kediri Kingdom, often performed spiritual retreats in a cave near the banks of the Brantas River. It is said that this is the historical place where the king realized liberation (Sanskrit: mokṣa). Thus, the Brantas River valley is considered a most auspicious site.
It is commonly believed that authentic badar besi mustika stones are present only in sacred locations. Therefore, this sacred elemental rock can be found in a mountainous environment and in holy caves in particular. Furthermore, genuine badar besi stones contain the astral body of a mystical khodam spirit, which indicate the spiritual purity of this particular substance. Just like jinns, a khodam spirit can manifest itself in any physical form or material object. However, only the most spiritually advanced khodam spirits are able to inhabit a mystical object like badar besi. This spiritual entity is like an angelic guide serving humans to enhance their spiritual practice as well as to protect them from malevolent jinns and black magic in general.
In addition, badar besi stones can offer the owner physical and metaphysical protection; hence, this type of amulet is immensely popular among practitioners of traditional Indonesian martial arts (pencak silat) and self-defense methods (kanuragan, kekabalan, etc.). Due to the mustika stone's inherent magical qualities, badar besi can make the human body invulnerable to sharp objects (e.g. thrusting weapons) and even gunfire. Also, badar besi has mystical properties which can prevent home fires. For reasons such as these, badar besi mustika stones are often also collected by military personnel (i.e. soldiers, marines and airmen) as well as police officers and firefighters.