Gemstone Info

Gemstone Description



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Ulexite, hydrated sodium calcium borate hydroxide, sometimes known as TV rock, is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. The natural fibers of ulexite conduct light along their long axes, by internal reflection.

Ulexite is a structurally complex mineral, with a basic structure containing chains of sodium, water and hydroxide octahedra. The chains are linked together by calcium, water, hydroxide and oxygen polyhedra and massive boron units. They are composed of three borate tetrahedra and two borate triangular groups.

TV rock

Ulexite is also known as TV rock due to its unusual optical characteristics. The fibers of ulexite act as optical fibers, transmitting light along their lengths by internal reflection. When a piece of ulexite is cut with flat polished faces perpendicular to the orientation of the fibers, a good-quality specimen will display an image of whatever surface is adjacent to its other side.

The fiber optic effect is the result of the polarization of light into slow and fast rays within each fiber, the internal reflection of the slow ray and the refraction of the fast ray into the slow ray of an adjacent fiber. An interesting consequence is the generation of three cones, two of which are polarized, when a laser beam obliquely illuminates the fibers. These cones can be seen when viewing a light source through the mineral.

Television stone / TV effect

Optical properties

Fibrous aggregates of ulexite project an image of an object on the opposite surface of the mineral. This optical property is common for synthetic fibers, but not in minerals, giving ulexite the nickname TV rock. This optical property is due to the reflections along twinned fibers, the most prominent twinning plane being on. The light is internally reflected over and over within each of the fibers that are surrounded by a medium of a lower refractive index. This optical effect is also the result of the large spaces formed by the sodium octahedral chains in the mineral structure. Synthetic fibers used for fiber optics transmit images along a bundle of threadlike crystals the same way naturally occurring ulexite reproduces images due to the existence of different indices of refractions between fibers. Additionally, if the object is colored, all of the colors are reproduced by ulexite. Parallel surfaces of ulexite cut perpendicular to the fibers produce the best image, as distortion in the size of the projected image will occur if the surface is not parallel to the mineral. Curiously, samples of stone are capable of producing a decent, rough image. Satin spar gypsum also exhibits this optical effect. However, the fibers are too coarse to transmit a decent image. The thickness of the fibers is proportional to the sharpness of the projected image.

Ulexite meaning

The following section is pseudo scientific and based on cultural beliefs.

Ulexite helps heal and balance physical vision. It can be used to help strengthen your eyesight and to overcome eye fatigue blurred or double vision.
It will remove wrinkles, ease headaches.
This stone will help in overcoming difficulties with the nervous system, especially with unexplained stabbing nerve pain. Ulexite will improve your memory and concentration.

Ulexite, from Boron, California, USA

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