Tourmaline crystals, growing amid feldspar crystals in a cavity in granite, from Paris, Me.
Tourmaline crystals, growing amid feldspar crystals in a cavity in granite, from Paris, Me.
Gold in quartz, from California
Gold in quartz, from California
Native silver in calcite
Native silver in calcite
Argentite, the black masses throughout the white quartz
Argentite, the black masses throughout the white quartz
Pyrargyrite as it appears after moderate exposure to the light.
Pyrargyrite as it appears after moderate exposure to the light.
Crystal form of Pyrargyrite
Crystal form of Pyrargyrite
Prousite as it appears after moderate exposure to the light
Prousite as it appears after moderate exposure to the light
Native copper from Michigan
Native copper from Michigan
Chalcopyrite in tetrahedrons and an occasional octahedron.
Chalcopyrite in tetrahedrons and an occasional octahedron.
Chalcocite crystals with the bluish tarnish
Chalcocite crystals with the bluish tarnish
Tetrahedrite crystals
Tetrahedrite crystals
Cuprite, the red crystals showing characteristic color, other showing the green tarnish of malachite
Cuprite, the red crystals showing characteristic color, other showing the green tarnish of malachite
Malachite (green) and azurite (blue), the two minerals shown together as they very commonly occur
Malachite (green) and azurite (blue), the two minerals shown together as they very commonly occur
Limonite
Limonite
The crystal form in which goethite is found,pis the prism faces,bandcare faces formed by beveling the edges of the prism,ois the pyramidal face characteristic of the ends
The crystal form in which goethite is found,pis the prism faces,bandcare faces formed by beveling the edges of the prism,ois the pyramidal face characteristic of the ends
Hematite, Clinton iron ore, oolitic
Hematite, Clinton iron ore, oolitic
Siderite crystals
Siderite crystals
Pyrite crystals
Pyrite crystals
Marcasite in concretionary form with radiate structure
Marcasite in concretionary form with radiate structure
Galena in crystals
Galena in crystals
Pyromorphite crystals (green)
Pyromorphite crystals (green)
Sphalerite, some the normal yellow and some crystals with the reddish tinge. (White is dolomite)
Sphalerite, some the normal yellow and some crystals with the reddish tinge. (White is dolomite)
Zincite
Zincite
Smithsonite in yellow crystals
Smithsonite in yellow crystals
Franklinite in octahedral crystals
Franklinite in octahedral crystals
Arsenopyrite, showing crystals massed so as to be incompletely developed
Arsenopyrite, showing crystals massed so as to be incompletely developed
Realgar as it usually occurs in powdery incrustations
Realgar as it usually occurs in powdery incrustations
Large crystal of stibnite, the light colored face is the one parallel to which cleavage occurs
Large crystal of stibnite, the light colored face is the one parallel to which cleavage occurs
Niccolite as a vein in slate
Niccolite as a vein in slate
Cobaltite, silver color, with pink tinge
Cobaltite, silver color, with pink tinge
Smaltite, pink is cobalt bloom
Smaltite, pink is cobalt bloom
Carnotite from southwest Colorado
Carnotite from southwest Colorado
Cinnabar
Cinnabar
Amethyst, not however deep enough colored for gems
Amethyst, not however deep enough colored for gems
Jasper, with botryoidal surface
Jasper, with botryoidal surface
Banded Agate from Brazil
Banded Agate from Brazil
Common Opal from Arizona
Common Opal from Arizona
Siliceous sinter or Geyserite from The Yellowstone Park
Siliceous sinter or Geyserite from The Yellowstone Park
A group of Microcline crystals from Pike’s Peak, Colo.
A group of Microcline crystals from Pike’s Peak, Colo.
Labradorite, showing multiple twinning (the striation), and the iridescent play of colors
Labradorite, showing multiple twinning (the striation), and the iridescent play of colors
Crystal form of a pyroxene;aandbprism faces,mthe beveled edge between two prism faces
Crystal form of a pyroxene;aandbprism faces,mthe beveled edge between two prism faces
Cross section of a pyroxene crystal showing the lines of intersection of the two cleavage planes
Cross section of a pyroxene crystal showing the lines of intersection of the two cleavage planes
Cross sections of pyroxenes, showing typical forms taken by crystals
Cross sections of pyroxenes, showing typical forms taken by crystals
Augite crystals, in crystalline limestone
Augite crystals, in crystalline limestone
The dodecahedron and the 24-sided figure characteristic of garnets
The dodecahedron and the 24-sided figure characteristic of garnets
The garnet, grossularite
The garnet, grossularite
The garnet alamandite
The garnet alamandite
Beryl of gem quality
Beryl of gem quality
Zircon in syenite
Zircon in syenite
Cyanite crystals in schist
Cyanite crystals in schist
A crystal of mica, showing basal cleavage
A crystal of mica, showing basal cleavage
Crystal form typical of topaz
Crystal form typical of topaz
A topaz crystal from Brazil
A topaz crystal from Brazil
Crystal form typical of staurolite when simple
Crystal form typical of staurolite when simple
A typical twin of staurolite
A typical twin of staurolite
Serpentine
Serpentine
Chlorite
Chlorite
Apatite crystals in crystalline calcite
Apatite crystals in crystalline calcite
The ends of apatite crystals showing common modes of termination
The ends of apatite crystals showing common modes of termination
A group of fluorite crystals
A group of fluorite crystals
A group of halite crystals
A group of halite crystals
Amber
Amber
Two bottles of petroleum, the left hand one with a paraffin base, the right hand one with an asphalt base
Two bottles of petroleum, the left hand one with a paraffin base, the right hand one with an asphalt base
Mica schist, with garnets
Mica schist, with garnets
Chlorite schist
Chlorite schist
Serpentine, composed of serpentine, hematite, and some calcite
Serpentine, composed of serpentine, hematite, and some calcite
Cube
Cube
Octahedron
Octahedron
Dodecahedron
Dodecahedron
A square prism
A square prism
Octahedron
Octahedron
A Rectangular prism
A Rectangular prism
Octahedron
Octahedron
The rectangular prism askew
The rectangular prism askew
The octahedron
The octahedron
A cross section of the prism with its edges beveled so that thebfaces are obliterated by themfaces, and a six-sided prism is formed (pseudo-hexagonal)
A cross section of the prism with its edges beveled so that thebfaces are obliterated by themfaces, and a six-sided prism is formed (pseudo-hexagonal)
Basal form of the triclinic system
Basal form of the triclinic system
The six-sided prism
The six-sided prism
The double pyramid
The double pyramid
The rhombohedron
The rhombohedron
Tetrahedrons showing characteristic manner in which tetrahedrite occurs
Tetrahedrons showing characteristic manner in which tetrahedrite occurs
A cube with the edges beveled and the corners cut in a form characteristic of cuprite
A cube with the edges beveled and the corners cut in a form characteristic of cuprite
Two intergrowing or twinned quartz crystals
Two intergrowing or twinned quartz crystals
Diagram of the typical quartz crystal,pprism faces,lleft hand rhombohedron,rright hand rhombohedron
Diagram of the typical quartz crystal,pprism faces,lleft hand rhombohedron,rright hand rhombohedron
A quartz crystal on which the left hand rhombohedron is represented by small faces while the right hand rhombohedron has large faces
A quartz crystal on which the left hand rhombohedron is represented by small faces while the right hand rhombohedron has large faces
Crystal forms of hematite,Athe rhombohedron with the edges beveled;Bthe tabular form, resulting from the excessive development of the twoofaces opposite each other
Crystal forms of hematite,Athe rhombohedron with the edges beveled;Bthe tabular form, resulting from the excessive development of the twoofaces opposite each other
A typical crystal of magnetite
A typical crystal of magnetite
The rhombohedron typical of siderite
The rhombohedron typical of siderite
The pyritohedron
The pyritohedron
The pyritohedron with certain of its edges beveled by the cube faces, to show the relationship of these two forms
The pyritohedron with certain of its edges beveled by the cube faces, to show the relationship of these two forms
The pyramid,nthe prism face,mthe beveled prism,pthe octahedral face, andothe edge of the octahedral faces beveled
The pyramid,nthe prism face,mthe beveled prism,pthe octahedral face, andothe edge of the octahedral faces beveled
The simple type of twinning
The simple type of twinning
A multiple twin where three crystals grow through each other
A multiple twin where three crystals grow through each other
Forms in which anglesite occurs:lthe pyramid face,pthe prism face,othe vertical edge of the prism beveled,mthe horizontal edge of the prism beveled,na further beveling of the horizontal edge of the prism.Dthe tabular,Ethe prismatic form
Forms in which anglesite occurs:lthe pyramid face,pthe prism face,othe vertical edge of the prism beveled,mthe horizontal edge of the prism beveled,na further beveling of the horizontal edge of the prism.Dthe tabular,Ethe prismatic form
A characteristic form in which sphalerite may occur; being the combination of,dthe dodecahedron,othe octahedron, andt, a 24-sided figure
A characteristic form in which sphalerite may occur; being the combination of,dthe dodecahedron,othe octahedron, andt, a 24-sided figure
Characteristic form for zincite crystals,nthe hexagonal prism, andppyramidal faces on it
Characteristic form for zincite crystals,nthe hexagonal prism, andppyramidal faces on it
Typical form of crystal of willemite:pthe prism,rrhombohedron faces on end, ½ra second lower rhombohedron
Typical form of crystal of willemite:pthe prism,rrhombohedron faces on end, ½ra second lower rhombohedron
Moss agates, showing the dendritic growth of manganitic minerals, like manganite or pyrolusite
Moss agates, showing the dendritic growth of manganitic minerals, like manganite or pyrolusite
Moss agates
Crystal form of manganite
Crystal form of manganite
Crystals of green corundum in syenite, from Montana
Crystals of green corundum in syenite, from Montana
Typical crystal forms of corundum:Athe elongated prism with the alternate corners cut by rhombohedral faces,Bthe tabular prism,Cthe double pyramid
Typical crystal forms of corundum:Athe elongated prism with the alternate corners cut by rhombohedral faces,Bthe tabular prism,Cthe double pyramid
Cassiterite, twinned crystals
Cassiterite, twinned crystals
The crystal form in which both cassiterite and rutile occur when in simple crystals,pprism faces,mbeveling of the prism,ooctahedral face,nbeveling of the edge between octahedral faces
The crystal form in which both cassiterite and rutile occur when in simple crystals,pprism faces,mbeveling of the prism,ooctahedral face,nbeveling of the edge between octahedral faces
Multiple twinning characteristic of rutile
Multiple twinning characteristic of rutile
Crystal of Spinel
Crystal of Spinel
Athe cleavage form, rhombohedron with the faces curved
Athe cleavage form, rhombohedron with the faces curved
Bthe rhombohedron with the corners cut, as it often occurs
Bthe rhombohedron with the corners cut, as it often occurs
Cthe form found in gypsum or anhydrite
Cthe form found in gypsum or anhydrite
Orthoclase, a cleavage piece,aandbthe perfect cleavage planes, andcthe imperfect cleavage plane
Orthoclase, a cleavage piece,aandbthe perfect cleavage planes, andcthe imperfect cleavage plane
Athe simple crystal
Athe simple crystal
Bthe twinned form
Bthe twinned form
Cthe twinned form in which the crystals are intergrowing
Cthe twinned form in which the crystals are intergrowing
Diagram of a multiple twin of a plagioclase feldspar
Diagram of a multiple twin of a plagioclase feldspar
Aa typical crystal
Aa typical crystal
Bcross section showing the intersection of cleavage planes
Bcross section showing the intersection of cleavage planes
CandDcross sections to show variations in outline
CandDcross sections to show variations in outline
Tremolite in silky fibrous crystals. Asbestos
Tremolite in silky fibrous crystals. Asbestos
Hornblende crystals in quartzite
Hornblende crystals in quartzite
Epidote crystals
Epidote crystals
Typical forms of epidote crystals;pprism faces,m,n,x, andybeveled edges of the prism,ooctahedral faces
Typical forms of epidote crystals;pprism faces,m,n,x, andybeveled edges of the prism,ooctahedral faces
Aside view;BandCends to show terminations;pprism faces,mbeveling of prism edges,ra low rhombohedron on the end,sthe opposite rhombohedron,bbasal face, and the other faces represent bevelings
Aside view;BandCends to show terminations;pprism faces,mbeveling of prism edges,ra low rhombohedron on the end,sthe opposite rhombohedron,bbasal face, and the other faces represent bevelings
A group of barite crystals
A group of barite crystals
Outline of the typical tabular barite crystal
Outline of the typical tabular barite crystal
The six-sided double pyramid, composed of three interpenetrating crystals, typical of witherite and strontianite
The six-sided double pyramid, composed of three interpenetrating crystals, typical of witherite and strontianite
The typical form of analcite
The typical form of analcite
A typical natrolite crystal
A typical natrolite crystal
The typical crystal form of stilbite
The typical crystal form of stilbite
A sheaf-like bundle of fibrous crystals, typical of stilbite
A sheaf-like bundle of fibrous crystals, typical of stilbite
A group of calcite crystals
A group of calcite crystals
Athe rhombohedron formed by cleavage
Athe rhombohedron formed by cleavage
Ba rhombohedral crystal truncated by the basal plane
Ba rhombohedral crystal truncated by the basal plane
Cthe scalenohedron
Cthe scalenohedron
Dthe scalenohedron truncated by the rhombohedron
Dthe scalenohedron truncated by the rhombohedron
Ethe scalenohedron on a prism
Ethe scalenohedron on a prism
Athe simple crystal
Athe simple crystal
Ba needle-like form, twinned
Ba needle-like form, twinned
Ccross section to show how the form may appear six-sided
Ccross section to show how the form may appear six-sided
Typical form of the anhydrite crystal
Typical form of the anhydrite crystal
A piece of gypsum looking on the surface of the perfect cleavage, and showing the two other cleavages as lines, intersecting at 66°. Twinning is also shown
A piece of gypsum looking on the surface of the perfect cleavage, and showing the two other cleavages as lines, intersecting at 66°. Twinning is also shown
A simple crystal of gypsum
A simple crystal of gypsum
Twin crystals of gypsum
Twin crystals of gypsum
Sulphur crystals
Sulphur crystals
Ice crystals, the top one, the end of a hexagonal prism; the two lower figures multiple twins as in snow flakes
Ice crystals, the top one, the end of a hexagonal prism; the two lower figures multiple twins as in snow flakes
The Devil’s Tower, Wyoming, an example of igneous rock with columnar structure, and resting on sedimentary rocks. Courtesy of the U. S. Geological Survey
The Devil’s Tower, Wyoming, an example of igneous rock with columnar structure, and resting on sedimentary rocks. Courtesy of the U. S. Geological Survey
A coarse granite
A coarse granite
Graphic granite
Graphic granite
Syenite
Syenite
Gabbro
Gabbro
Basalt-porphyry. The large white crystals are phenocrysts of plagioclase feldspar
Basalt-porphyry. The large white crystals are phenocrysts of plagioclase feldspar
Basalt-obsidian
Basalt-obsidian
Amgydoloid
Amgydoloid
The north face of Scott’s Bluff, Neb., showing sedimentary sandstones above and clays below. The type of erosion is characteristic of arid regions. Courtesy of the U. S. Geological Survey
The north face of Scott’s Bluff, Neb., showing sedimentary sandstones above and clays below. The type of erosion is characteristic of arid regions. Courtesy of the U. S. Geological Survey
Breccia
Breccia
Conglomerate
Conglomerate
Calcareous shale
Calcareous shale
Coquina
Coquina
Foramenifera from Chalk; enlarged about 25 diameters
Foramenifera from Chalk; enlarged about 25 diameters
Encrinal Limestone; fragments of the stems, arms and body of Crinoids
Encrinal Limestone; fragments of the stems, arms and body of Crinoids
Adiatomaceous earth magnified 50 times
Adiatomaceous earth magnified 50 times
BandCtwo diatoms from the above enlarged 250 times. After Gravelle, by the courtesy of Natural History
BandCtwo diatoms from the above enlarged 250 times. After Gravelle, by the courtesy of Natural History
A metamorphic rock, showing the contortion of layers due to expansion under heat
A metamorphic rock, showing the contortion of layers due to expansion under heat
A conglomerate partly metamorphosed to a gneiss. Note the flattened pebbles and the alternation of the intermediate material to mica scales, etc.
A conglomerate partly metamorphosed to a gneiss. Note the flattened pebbles and the alternation of the intermediate material to mica scales, etc.
A typical gneiss
A typical gneiss
Phyllite
Phyllite
A white marble, with black streaks due to graphite
A white marble, with black streaks due to graphite
Claystones, simple and compound
Claystones, simple and compound
A line concretion, which on splitting disclosed a fern leaf of the age of the coal measures
A line concretion, which on splitting disclosed a fern leaf of the age of the coal measures
A septeria from Seneca Lake, N. Y.
A septeria from Seneca Lake, N. Y.
Pisolite
Pisolite
A geode filled with quartz crystals
A geode filled with quartz crystals
A quartz pebble from the bed of a New England brook
A quartz pebble from the bed of a New England brook
A pebble of schist and granite from the foot of Mt. Toby, Mass.
A pebble of schist and granite from the foot of Mt. Toby, Mass.
An iron-nickel meteorite, of 23 lbs. which fell in Claiborne Co., Tenn.
An iron-nickel meteorite, of 23 lbs. which fell in Claiborne Co., Tenn.
An etched slice of an iron meteorite which fell in Reed City, Osceola Co., Mich.
An etched slice of an iron meteorite which fell in Reed City, Osceola Co., Mich.
A stony meteorite, about natural size, which fell in 1875, in Iowa Co., Iowa
A stony meteorite, about natural size, which fell in 1875, in Iowa Co., Iowa