Quartz
Six-sided Crystal shape; Hardness 7; Specific Gravity 2.65; glassy (concoidal) fracture. Color is quite variable (there are milky quartz, smoky quartz, rose quartz, amethyst (purple), aventurine (green), carnelian (orange), and other quartz varieties). Attractive colored quartz are sometimes called "agates" or "jasper." Quartz is used to make glass.
Orthoclase feldspar
Hardness 6; Color white to gray, commonly pink. There are two prominent cleavage directions at right angles. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Plagiclase feldspar
Hardness 6; Color white to gray. There are two prominent cleavage directions at right angles. Ca-feldspars commonly have striations, whcih are barely visible grooves, on one cleavage face. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Fluorite
Four directions of cleavage, although all four directions may not be obvious on a typical specimen. Hardness 4; Crystals are cubic; Color variable.
Hornblende
Black color; Hardness 5-6; Cleavage in two directions with intersections at 56 and 124 degrees, though this is not necessarily obvious in your specimens. Note how specimen readily reflects light. Fine lines that run through the mineral are caused by the atoms forming chains.
Garnet
Color variable, hardness 6.5-7.5. Actually a group of six silicate minerals with twelve-sided crystals. Colors include red, brown, and green. Used as an abrasive, in sandpaper.
Talc
Hardness 1; Luster pearly; Color variable but often white. Low hardness causes a greasy or soapy feel. Used in talcum powder because of its softness, also has good water absorption properties.
Apatite
Hardness 5; Color typically white to green. Important source of phosphate, which is used agriculturally. The composition of our bones and teeth.
Halite
Colorless to white; Hardness 2.5; Taste salty, dissolves easily in water. Three perpendicular directions of cleavage (breaks into cubes). Used as a condiment or for preserving meat.
Calcite
Hardness 3; Color variable but usually clear-white; Chemically reacts with hydrochloric acid; Cleavage in three non-perpendicular directions. Typically has a rhombohedral shape. When transparent, calcite refracts light into two directions (double refraction). Calcite and a related mineral called aragonite make up seashells.
Graphite
Hardness 1; Gray-black color; Specific Gravity 2.0; Cleavage in one direction but not typically obvious in hand-specimen. Used in pencil leads and light-weight composites for aircraft and tennis rackets, when mixed with oil makes a good lubricant, also used as a semi-conductor.
Olivine
Color typically green, with a granular texture; hardness 6.5-7.0 This is the composition believed to make up most of the mantle of the earth.
Sulfur
Distinctive yellow color, also with a obvious odor (though that is not obvious in our lab specimens). A common by-product of industrial operations, an important pollutant.
Corundum
Hardness 9; Color typically deep red; Crystal shape six-sided, sometimes visible; Used as an abrasive or cutting agent. Gem qualities called ruby or sapphire.
Biotite
Color black; Cleavage in one direction. Dark color is caused by the presence of magnesium in the molecular structure.
Muscovite
Cleavage in one direction; Color variable but typically white with metallic luster. Used as a substitute for glass, especially for high-temperature applications. Color is due to the presence of aluminum in the molecular structure.
Gypsum
Hardness 2; Color typically white or light-colored; Cleavage predominately in 2 directions, but there can be a less pronounced cleavage in a third direction. Varieties include satin spar and alabaster. Because of softness this material is often used in carvings. Also used in plaster-of-Paris.
Topaz
Hardness 8. Not an especially useful or important mineral, and thus not included in your tray, but included here because it is on the Mohs' hardness scale.
Diamond
Hardness 10, Color variable but typically colorless, rarely occurs in large sizes. Used as a cutting agent in saws. Despite their hardness diamonds can still be fractured.
Return to Physical Geology Syllabus
Return to Kevin McCartney's homepage
Quartz
Six-sided Crystal shape; Hardness 7; Specific Gravity 2.65; glassy (concoidal) fracture. Color is quite variable (there are milky quartz, smoky quartz, rose quartz, amethyst (purple), aventurine (green), carnelian (orange), and other quartz varieties). Attractive colored quartz are sometimes called "agates" or "jasper." Quartz is used to make glass.
Orthoclase feldspar
Hardness 6; Color white to gray, commonly pink. There are two prominent cleavage directions at right angles. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Plagiclase feldspar
Hardness 6; Color white to gray. There are two prominent cleavage directions at right angles. Ca-feldspars commonly have striations, whcih are barely visible grooves, on one cleavage face. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Fluorite
Four directions of cleavage, although all four directions may not be obvious on a typical specimen. Hardness 4; Crystals are cubic; Color variable.
Hornblende
Black color; Hardness 5-6; Cleavage in two directions with intersections at 56 and 124 degrees, though this is not necessarily obvious in your specimens. Note how specimen readily reflects light. Fine lines that run through the mineral are caused by the atoms forming chains.
Garnet
Color variable, hardness 6.5-7.5. Actually a group of six silicate minerals with twelve-sided crystals. Colors include red, brown, and green. Used as an abrasive, in sandpaper.
Talc
Hardness 1; Luster pearly; Color variable but often white. Low hardness causes a greasy or soapy feel. Used in talcum powder because of its softness, also has good water absorption properties.
Apatite
Hardness 5; Color typically white to green. Important source of phosphate, which is used agriculturally. The composition of our bones and teeth.
Halite
Colorless to white; Hardness 2.5; Taste salty, dissolves easily in water. Three perpendicular directions of cleavage (breaks into cubes). Used as a condiment or for preserving meat.
Calcite
Hardness 3; Color variable but usually clear-white; Chemically reacts with hydrochloric acid; Cleavage in three non-perpendicular directions. Typically has a rhombohedral shape. When transparent, calcite refracts light into two directions (double refraction). Calcite and a related mineral called aragonite make up seashells.
Graphite
Hardness 1; Gray-black color; Specific Gravity 2.0; Cleavage in one direction but not typically obvious in hand-specimen. Used in pencil leads and light-weight composites for aircraft and tennis rackets, when mixed with oil makes a good lubricant, also used as a semi-conductor.
Olivine
Color typically green, with a granular texture; hardness 6.5-7.0 This is the composition believed to make up most of the mantle of the earth.
Sulfur
Distinctive yellow color, also with a obvious odor (though that is not obvious in our lab specimens). A common by-product of industrial operations, an important pollutant.
Corundum
Hardness 9; Color typically deep red; Crystal shape six-sided, sometimes visible; Used as an abrasive or cutting agent. Gem qualities called ruby or sapphire.
Biotite
Color black; Cleavage in one direction. Dark color is caused by the presence of magnesium in the molecular structure.
Muscovite
Cleavage in one direction; Color variable but typically white with metallic luster. Used as a substitute for glass, especially for high-temperature applications. Color is due to the presence of aluminum in the molecular structure.
Gypsum
Hardness 2; Color typically white or light-colored; Cleavage predominately in 2 directions, but there can be a less pronounced cleavage in a third direction. Varieties include satin spar and alabaster. Because of softness this material is often used in carvings. Also used in plaster-of-Paris.
Topaz
Hardness 8. Not an especially useful or important mineral, and thus not included in your tray, but included here because it is on the Mohs' hardness scale.
Diamond
Hardness 10, Color variable but typically colorless, rarely occurs in large sizes. Used as a cutting agent in saws. Despite their hardness diamonds can still be fractured.
Return to Physical Geology Syllabus
Return to Kevin McCartney's homepage
Six-sided Crystal shape; Hardness 7; Specific Gravity 2.65; glassy (concoidal) fracture. Color is quite variable (there are milky quartz, smoky quartz, rose quartz, amethyst (purple), aventurine (green), carnelian (orange), and other quartz varieties). Attractive colored quartz are sometimes called "agates" or "jasper." Quartz is used to make glass.
Hardness 6; Color white to gray, commonly pink. There are two prominent cleavage directions at right angles. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Hardness 6; Color white to gray. There are two prominent cleavage directions at right angles. Ca-feldspars commonly have striations, whcih are barely visible grooves, on one cleavage face. Feldspars weather to form dirts and clay, and consequently are important in agriculture and pottery.
Four directions of cleavage, although all four directions may not be obvious on a typical specimen. Hardness 4; Crystals are cubic; Color variable.
Black color; Hardness 5-6; Cleavage in two directions with intersections at 56 and 124 degrees, though this is not necessarily obvious in your specimens. Note how specimen readily reflects light. Fine lines that run through the mineral are caused by the atoms forming chains.
Color variable, hardness 6.5-7.5. Actually a group of six silicate minerals with twelve-sided crystals. Colors include red, brown, and green. Used as an abrasive, in sandpaper.
Hardness 1; Luster pearly; Color variable but often white. Low hardness causes a greasy or soapy feel. Used in talcum powder because of its softness, also has good water absorption properties.
Hardness 5; Color typically white to green. Important source of phosphate, which is used agriculturally. The composition of our bones and teeth.
Colorless to white; Hardness 2.5; Taste salty, dissolves easily in water. Three perpendicular directions of cleavage (breaks into cubes). Used as a condiment or for preserving meat.
Hardness 3; Color variable but usually clear-white; Chemically reacts with hydrochloric acid; Cleavage in three non-perpendicular directions. Typically has a rhombohedral shape. When transparent, calcite refracts light into two directions (double refraction). Calcite and a related mineral called aragonite make up seashells.
Hardness 1; Gray-black color; Specific Gravity 2.0; Cleavage in one direction but not typically obvious in hand-specimen. Used in pencil leads and light-weight composites for aircraft and tennis rackets, when mixed with oil makes a good lubricant, also used as a semi-conductor.
Color typically green, with a granular texture; hardness 6.5-7.0 This is the composition believed to make up most of the mantle of the earth.
Distinctive yellow color, also with a obvious odor (though that is not obvious in our lab specimens). A common by-product of industrial operations, an important pollutant.
Hardness 9; Color typically deep red; Crystal shape six-sided, sometimes visible; Used as an abrasive or cutting agent. Gem qualities called ruby or sapphire.
Color black; Cleavage in one direction. Dark color is caused by the presence of magnesium in the molecular structure.
Cleavage in one direction; Color variable but typically white with metallic luster. Used as a substitute for glass, especially for high-temperature applications. Color is due to the presence of aluminum in the molecular structure.
Hardness 2; Color typically white or light-colored; Cleavage predominately in 2 directions, but there can be a less pronounced cleavage in a third direction. Varieties include satin spar and alabaster. Because of softness this material is often used in carvings. Also used in plaster-of-Paris.
Hardness 8. Not an especially useful or important mineral, and thus not included in your tray, but included here because it is on the Mohs' hardness scale.
Hardness 10, Color variable but typically colorless, rarely occurs in large sizes. Used as a cutting agent in saws. Despite their hardness diamonds can still be fractured.
Orthoclase feldspar
Plagiclase feldspar
Fluorite
Hornblende
Garnet
Talc
Apatite
Halite
Calcite
Graphite
Olivine
Sulfur
Corundum
Biotite
Muscovite
Gypsum
Topaz
Diamond
Return to Physical Geology Syllabus Return to Kevin McCartney's homepage