Rock Picture of the Week Archive 6

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Barite
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Barite, or Baryte,  (BaSO4) is generally found in sedimentary rocks and is the primary source of barium. It is also used as a weighting agent in drilling wells, a pigment in paint, and a medical agent for taking xrays of the intestines.
Barite is too soft to be effectively used as jewelry.



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 Bixbyite
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Bixbyite ((Mn,Fe)2O3) is a manganese iron oxide. The amount of iron in the formula varies greatly. This specimen came from Thomas, Utah.
It is submetalic, opaque, and is fairly rare. The main use of Bixbyite is as specimens.

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Creedite
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Creedite (Ca3Al2F4SO4(F,OH)4-2(H2O)) is a fairly rare mineral found in oxidized ores, usually associated with Fluorite. It is named for the Creed Quadrangle, Colorado, where it was discovered.
The color is generally a shade of purple and it is too soft to be used in jewelry.

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Sulfur
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Sulfur, or Sulphur, (S) is a common element and mineral. It is very reactive and exists in combination with many minerals. Some life forms use it instead of oxygen to sustain life.
Native Sulfur makes an attractive specimen, but can easily be damaged by temperature changes, moisture, or rough handling.

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Selenite
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Selenite (CaSO4-2H2O) is the name often given to the crystalline form of Gypsum. It is common in sedimentary formations, especially where seas or lakes have evaporated.
Although the crystals are very attractive, they are too soft to be used in jewelry.

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Aquamarine Tourmaline and Quartz
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

Aquamarine (Be3Al2Si6O18), the long bluish crystals, Tourmaline, or Schorl (formula complicated and variable) are the dark crystals, and Quartz (SiO2), the pale smokey crystals, make up this attractive specimen from Erongo, Namibia.

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Vanadinite and Magnesite on Barite
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Photo by Jim Bryan

From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.

This specimen contains red/orange Vanadinite (Pb5(VO4)3Cl), and brown Magnesite (MgCO3), on white Barite (BaSO4). This one came from Morocco.

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Pyrite
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Photo by Jim Bryan
From the private collection of Mike & Chris Whittier of Rocks in a Hard Place.
Pyrite (FeS2) is a very common sulfide mineral found in many different types of rock formations. These cubes are about an inch wide.
The name is derived from the word "fire", because it will create hot sparks when struck by iron or a harder rock.
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Mortar and Pestle
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Photo by Jim Bryan

This mortar with pestle is about 10 inches wide and is made of sandstone, but they were made in many sizes and from different materials.
The Native Americans used them mainly for food preparation.

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