Epidote is a silicate mineral, a calcium aluminum iron silicate. It has a hardness of 6 to 7 on the Mohs scale. One of its distinguishing characteristics is strong pleochroism, where crystals display different colors -- green, brown and yellow -- as they
This mineral beauty, dubbed the "snow angel," was discovered during the digging of a well in India. The specimen is a silicate mineral called apophyllite-(KF), which appears in volcanic rocks. Shine On: Photos of Dazzling Mineral Specimens
Benitoite is a rare blue barium titanium silicate mineral, found in hydrothermally altered serpentinite. It fluoresces under short wave ultraviolet light, appearing bright blue to bluish white in color. First described in 1907 by George D.
Astrophyllite, from the mineralogical museum in Kirovsk in Russia. A very rare mineral, and rather soft so particularly fragile. Astrophyllite is a very rare, brown to golden-yellow hydrous potassium iron titanium silicate mineral. Belonging to the astrophyllite group, astrophyllite may be classed either as an inosilicate, phyllosilicate, or an intermediate between the two.
moqui marbles, utah Iron oxide concretions (Moqui marbles) Moqui Marbles, hematite concretions, from the Navajo Sandstone of southeast Utah. The Navajo Sandstone is also well known among rockhounds for its hundreds of thousands of iron oxide concretions
This cm) tourmaline goes up for auction June Tourmalines are boron silicate minerals that get their rainbow-like colors from various elements such as iron, sodium or magnesium. This specimen comes from Brazil.