Tiger eye is a popular gemstone recognized for its distinctive chatoyancy, a shimmering effect resembling a cat’s eye. For practical purposes, tiger eye is generally not considered magnetic. However, a deeper scientific understanding reveals a more nuanced answer regarding its subtle magnetic characteristics.
Understanding Mineral Magnetism
Minerals display varying degrees of interaction with magnetic fields, categorized into different types of magnetism. Ferromagnetism describes materials that show a strong attraction to a magnetic field and can retain their magnetic properties even after the field is removed, similar to iron, nickel, or cobalt.
Paramagnetism involves a weak attraction to a magnetic field; these materials lose their magnetic properties once the external field is removed. Many minerals containing elements like iron or aluminum exhibit this type of weak attraction, often imperceptible without specialized equipment. In contrast, diamagnetism is a weak repulsion from a magnetic field. Most minerals, including quartz, are diamagnetic, and this repulsion is typically very subtle.
The Magnetic Properties of Tiger Eye
Tiger eye primarily consists of quartz, which is a diamagnetic mineral. The gemstone’s characteristic golden-brown color and the unique chatoyant luster are due to the presence of fibrous inclusions. These inclusions originate from altered crocidolite, which has transformed into goethite.
Goethite is an iron oxyhydroxide mineral that contains iron, an element known to contribute to magnetic properties. Specifically, goethite exhibits weak paramagnetism. Therefore, tiger eye, due to its goethite content, is technically paramagnetic and experiences a very slight attraction to a strong magnetic field. This attraction is usually too faint to be detected by a common household magnet.
Tiger Eye Versus Truly Magnetic Stones
The magnetic behavior of tiger eye differs significantly from minerals widely recognized for their strong magnetic properties. Minerals like magnetite, an iron oxide, are strongly ferrimagnetic, meaning they are notably attracted to a magnet and can even become permanent magnets.
Hematite, another iron oxide, is often confused due to its iron content but is generally considered non-magnetic or only very weakly magnetic in common forms. While some sources suggest hematite inclusions can cause weak magnetic attraction in tiger eye, this is not a consistent property of tiger eye itself. Understanding these distinctions helps clarify why tiger eye is not magnetic in the practical sense, unlike minerals such as magnetite.
Testing Your Tiger Eye Stone
For those interested in testing their tiger eye stone, a strong neodymium magnet is recommended. Household magnets are typically too weak to detect the subtle paramagnetic response of tiger eye. If the stone is genuine tiger eye, it will likely show no discernible attraction or, at most, an extremely faint, almost imperceptible pull.
A strong attraction indicates that the stone is either not genuine tiger eye or contains significant inclusions of other, more magnetic minerals like magnetite or substantial hematite. Tiger eye’s properties are inherent, and attempting to “magnetize” the stone will not change its natural response.