kristálygoniométer

A kristálygoniométer is an instrument used to measure the angles between the faces of crystals. The word itself is derived from Greek, meaning "crystal angle measurer." Its primary function is to determine the precise geometric relationship between the surfaces of a crystal specimen, which is a fundamental property in crystallography.

There are two main types of kristálygoniométer: contact and reflecting. Contact goniometers, also known as goniometers, consist of two adjustable arms that are brought into contact with adjacent crystal faces. The angle between these arms is then read off a graduated scale. Reflecting goniometers, developed later, are more precise and utilize optical principles. They employ a telescope and a mirrored surface on the crystal face. Light is reflected from the face into the telescope, and the rotation of the crystal is measured to determine the face angles.

The measurements obtained from a kristálygoniométer are crucial for identifying mineral species and understanding their internal atomic structure. Different crystal systems and minerals exhibit characteristic interfacial angles. Therefore, accurate measurements are vital for both scientific research and practical applications such as mineral exploration and gemology. Early versions of the kristálygoniométer were developed in the late 18th and early 19th centuries, significantly advancing the field of crystallography.