THE
MINERAL RHODIZITE
- Chemistry: (K, Cs)Be4Al4(B, Be)12O28, Potassium Cesium Beryllium Aluminum Borate.
- Class: Carbonates
- Subclass: Borates
- Uses: As mineral specimens and sometimes cut as a gemstone.
Specimens
Rhodizite is a rare potassium cesium beryllium aluminum borate mineral. Just its chemistry gives away its rarity. Specimens come from only a few areas: a couple of sites in the Ural Mountains, and a few sites in Madagascar. Rhodizite is remarkable for not only its chemistry but its bright adamantine luster and high degree of hardness. Both these properties lend themselves well to the fashioning of a gemstone. Rhodizite is too rare and generally lacks good color to be used often as a gemstone however.
Do not confuse rhodizite for other similar sounding minerals such as
the silicate mineral
rhodonite,
the carbonate mineral
rhodochrosite
or the silicate mineral
PHYSICAL CHARACTERISTICS:
- Color is colorless to white or gray and also with pale tints of yellow.
- Luster is vitreous to adamantine or silky.
- Transparency: Crystals are transparent to translucent.
- Crystal System is isometric.
- Crystal Habits include dodecahedral crystals and embedded grains.
- Cleavage is absent.
- Hardness is 8
- Specific Gravity is approximately 3.3 - 3.4 (slightly above average for translucent minerals)
- Streak is white.
- Other Characteristics: Index of refraction is 1.69 .
- Associated Minerals include the red tourmaline elbaite.
- Notable Occurrences include Antandrokomby, the Sahatany Valley of the Antisarabe area and Manjakandriana, Madagascar and Sarapulsk and Schaitansk, Mursinsk in the Urals Mountains of Russia.
- Best Field Indicators are crystal habit, color, associations, locality, lack of cleavage and the unusually high degree of hardness.
 Amethyst Galleries' Mineral Gallery MINERALS |
RHODIZITE specimen rhz-1$ 200.00
Dims: 1.4" x 1.1" x 0.8" (3.6 x 2.8 x 2.0 cm)
Wt: 22.1 g
Sahatany Valley, Antisarabe area, Madagascar
When I first saw this odd thumbnail specimen, I thought that it was just another green grossular specimen. Not so! It is actually a rare borate mineral that has a similar color and structure to that of the garnet family. There are 3 discernable crystals on this specimen. The largest has dimensions of 0.6 x 0.5 x 0.5" (1.5 x 1.3 x 1.3 cm) and shows moderate damage in the form of a scuffed, missing point. Other than that, it is in good condition and shows a rather warped variation of the isometric system that I cannot identify. Its edges are sharp and its faces are clean- some show a dull, waxy luster, whereas others have a much brighter, pearly luster. These brighter faces also show triangular growth patterns that are quite subtle but detailed (see the close-up image). The crystals are all a pale green in color and appear to be heavily internally fractured- they are only moderately to dimly translucent. The smaller crystals do not exceed 0.1" (3 mm) in any dimension. One of these has a rather odd, triangular dipyramidal form; I would have expected it to be octahedral. They rest on a base that appears to be made up of both smoky quartz and some type of feldspar.
rhz-1 ($200.00)Sahatany Valley, Antisarabe area, Madagascar
RHODIZITE specimen rhz-2
$ 190.00
$ 190.00
Dims: 1.4 x 1.1 x 1.0" (3.6 x 2.8 x 2.5 cm)
Wt: 25.1 g w/ base
Sahatany Valley, Antisarabe area, Madagascar
At least two intergrown Rhodizite crystals rest on the quartz base of this thumbnail specimen. The smaller one is mostly intergrown with the larger- its visible dimensions are 0.3 x 0.3 x 0.1" (9 x 8 x 2 mm). The other crystal is much larger, measuring 0.9 x 0.6 x 0.5" (2.3 x 1.5 x 1.3 cm), so I will concentrate on it. Its cubic-based form is highly warped, and appears to be a combination of the octahedral and the dodecahedral forms. Nonetheless, its edges are still well-defined and its faces are lightly striated but clean, and possess a very dull, waxy luster. It has a uniform, pale green coloration and is mostly translucent, though there are a few visible patches of faint transparence. The quartz base on which it formed is badly broken, but has definite crystal form. It is hot-glued onto a flat, square acrylic base.
rhz-2 ($190.00)
Sahatany Valley, Antisarabe area, Madagascar
RHODIZITE specimen rhz-3
$ 49.00
$ 49.00
Dims: 0.5 x 0.4 x 0.4" (1.3 x 1.1 x 0.9 cm)
Wt: 2 g
Ambalanilaifotsy, Fenoarive, Ambatofinandrahana, Madagascar
This small thumbnail specimen consists of a single, loose Rhodizite crystal. This crystal is in fair condition, showing considerable damage, and has a warped, incomplete dodecahedral form. Its pale, yellow-green color and dull pearly luster are standard for its species, and it is translucent and cloudy. The crystal is affixed to a flat, acrylic base with a removable putty.
rhz-3 ($ 49.00)
Ambalanilaifotsy, Fenoarive, Ambatofinandrahana, Madagascar
RHODIZITE specimen rhz-4
$ 48.00
$ 48.00
Dims: 1.0 x 0.9 x 0.8" (2.4 x 2.2 x 2.0 cm)
Wt: 0.4 oz. (10 g)
Sahanivotry, south of Antsirabe, Madagascar
This thumbnail piece consists of at least one nearly complete Rhodizite crystal that is partly embedded in a rusty base rock. This crystal has dimensions of about 0.4 x 0.4 x 0.3" (9 x 9 x 7 mm) and is in good condition, showing a small amount of fresh damage on its front. Its octahedral form is obviously warped in some areas but still very good, showing some interesting secondary faces. Its dull yellow color and pearly luster are standard for the specie, and it is transparent but only dimly clear due to many internal fractures and inclusions. Other Rhodizite crystals appear to be present in the host rock, but these are generally badly broken and incomplete. The piece is affixed inside a plastic thumbnail box.
rhz-4 ($ 48.00)
Sahanivotry, south of Antsirabe, Madagascar