This figure, representing Acanthite, an orthrohombic  crystal, shows a combination of the following forms: (a), (b), (c), (l), (m), (o), (e), (d), (k), (p), (s), (r), and (n).

Acanthite

This figure, representing Acanthite, an orthrohombic crystal, shows a combination of the following forms:…

"Triclinic. Usually in tabular crystals parallel to brachypinacoid." — Ford, 1912

Albite

"Triclinic. Usually in tabular crystals parallel to brachypinacoid." — Ford, 1912

"Triclinic. Sometimes elongated parallel to b crystal axis." — Ford, 1912

Albite

"Triclinic. Sometimes elongated parallel to b crystal axis." — Ford, 1912

"Triclinic. Twinning very common, according to the albite law and evidenced by fine striation lines on the better cleavage surface." — Ford, 1912

Albite

"Triclinic. Twinning very common, according to the albite law and evidenced by fine striation lines…

The form 3O3, {311} on Ammonium Chloride (Sal Ammoniac) may have only six of its twenty-four planes developed, and in this way give rise to a form resembling a tetragonal trapezohedron.

Ammonium Chloride

The form 3O3, {311} on Ammonium Chloride (Sal Ammoniac) may have only six of its twenty-four planes…

Amphibole.

Amphibole

Amphibole.

Amphibole.

Amphinole

Amphibole.

"Monoclinic. Crystals prismatic in habit; the prism faces make angles of 55 and 125 degrees with each other." — Ford, 1912

Amphibole

"Monoclinic. Crystals prismatic in habit; the prism faces make angles of 55 and 125 degrees with each…

"Monoclinic. Crystals prismatic in habit; the prism faces make angles of 55 and 125 degrees with each other." — Ford, 1912"

Amphibole

"Monoclinic. Crystals prismatic in habit; the prism faces make angles of 55 and 125 degrees with each…

This figure reproduces a combination of orthorhombic forms observed on crystals of aluminum orthosilicate, or Andalusite: (a), (b), (c), (m), (l), (n), (r), (p), (s), and (k).

Andalusite

This figure reproduces a combination of orthorhombic forms observed on crystals of aluminum orthosilicate,…

Anglesite.

Anglesite

Anglesite.

"A complex crystal of apatite with the faces of a third-order pyramid upon it." — Ford, 1912

Apatite

"A complex crystal of apatite with the faces of a third-order pyramid upon it." — Ford, 1912

"Hexagonal; tri-pyramidal. Crystals usually long prismatic in habit; sometimes short prismatic or tabular. Usually terminated by prominent pyramid of first order and frequently a basal plane." — Ford, 1912

Apatite

"Hexagonal; tri-pyramidal. Crystals usually long prismatic in habit; sometimes short prismatic or tabular.…

"Hexagonal; tri-pyramidal. Crystals usually long prismatic in habit; sometimes short prismatic or tabular. Usually terminated by prominent pyramid of first order and frequently a basal plane." — Ford, 1912

Apatite

"Hexagonal; tri-pyramidal. Crystals usually long prismatic in habit; sometimes short prismatic or tabular.…

Apophyllite.

Apophyllite

Apophyllite.

Apophyllite.

Apophyllite

Apophyllite.

"Tetragonal. Usually shows a combination of prism of second order, pyramid of first and basal plane." — Ford, 1912

Apophyllite

"Tetragonal. Usually shows a combination of prism of second order, pyramid of first and basal plane."…

"Orthorhombic. Acicular pyramidal; consisting of a prism terminated by a combination of a very steep pyramid and brachydome." — Ford, 1912

Aragonite

"Orthorhombic. Acicular pyramidal; consisting of a prism terminated by a combination of a very steep…

"Orthorhombic. Tabular; consisting of prominent brachypinacoid faces modified by a prism and a low brachydome." — Ford, 1912

Aragonite

"Orthorhombic. Tabular; consisting of prominent brachypinacoid faces modified by a prism and a low brachydome."…

"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low brachydomes. The brachydomes are usually striated parallel to the brachy-axis." — Ford, 1912

Arsenopyrite

"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low…

"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low brachydomes. The brachydomes are usually striated parallel to the brachy-axis. Twinned at times, giving stellate groups; the different individuals of the twin groups being distinguished from each other by the direction of the striations upon them." — Ford, 1912

Arsenopyrite

"Orthohombric. Usually in tabular diamond-shaped crystals, formed by a short prism terminated by low…

Iron Sulpharsenide (Arsenopyrite), bounded by ∞P, {110} (M), and 1/3P∞̆, {013} (r), forms penetration twins of two individuals, where P∞̄, {101} acts as twinning plane.

Arsenopyrite

Iron Sulpharsenide (Arsenopyrite), bounded by ∞P, {110} (M), and 1/3P∞̆, {013} (r), forms penetration…

Axinite.

Axinite

Axinite.

"Triclinic. Crystals usually thin with sharp edges but varied in habit." — Ford, 1912

Axinite

"Triclinic. Crystals usually thin with sharp edges but varied in habit." — Ford, 1912

Natural crystal. 6, axinite.

Axinite

Natural crystal. 6, axinite.

Barite.

Barite

Barite.

"Orthohombic. Crystals usually tabular parallel to base; often diamond shaped because of the presence of a short prism. Both macro- and brachydomes usually present, either beveling the corners of the diamond-shaped crystals, or if the prism faces are wanting, beveling the edges of the tavles and forming rectangular prismatic-shaped crystals elongated parallel to either the brachy- or macro-axis." — Ford, 1912

Barite

"Orthohombic. Crystals usually tabular parallel to base; often diamond shaped because of the presence…

"Orthohombic. Crystals usually tabular parallel to base; often diamond shaped because of the presence of a short prism. Both macro- and brachydomes usually present, either beveling the corners of the diamond-shaped crystals, or if the prism faces are wanting, beveling the edges of the tavles and forming rectangular prismatic-shaped crystals elongated parallel to either the brachy- or macro-axis." — Ford, 1912

Barite

"Orthohombic. Crystals usually tabular parallel to base; often diamond shaped because of the presence…

This form shows a crystal of Barium Nitrate exhibiting isometric tetartohedral crystallization.

Barium Nitrate

This form shows a crystal of Barium Nitrate exhibiting isometric tetartohedral crystallization.

Basalt, showing typical diabasic structure of lath-shaped crystals of plagioclase.

Basalt

Basalt, showing typical diabasic structure of lath-shaped crystals of plagioclase.

"Cells of Beet-root, containing conglomerate crystals." — Encyclopedia Britanica, 1893

Beet-root

"Cells of Beet-root, containing conglomerate crystals." — Encyclopedia Britanica, 1893

"Hexagonal. Strong prismatic habit. Frequently vertically striated and grooved. Forms usually present consist only of prism of first order and base." — Ford, 1912

Beryl

"Hexagonal. Strong prismatic habit. Frequently vertically striated and grooved. Forms usually present…

"Hexagonal. Strong prismatic habit. Frequently vertically striated and grooved. Forms usually present consist only of prism of first order and base. Small pyramid faces of both the first and second orders sometimes occur, but the pyramid faces are rarely prominent." — Ford, 1912

Beryl

"Hexagonal. Strong prismatic habit. Frequently vertically striated and grooved. Forms usually present…

Beryl is a mineral containing beryllium and aluminum in the form of a silicate.

Crystal of Beryl

Beryl is a mineral containing beryllium and aluminum in the form of a silicate.

This form shows a tetrahedron (o) with its edges beveled by the trigonal tristetrahedron (l), and its angles replaced by the rhombic dodecahedron.

Beveled Tetrahedron

This form shows a tetrahedron (o) with its edges beveled by the trigonal tristetrahedron (l), and its…

This figure represents a crystal of Boron.

Boron

This figure represents a crystal of Boron.

"Orthohombric. Crystals usually short prismatic to tabular. Sometimes quite complex with many prism, pyramid and dome faces. Frequently twinned, giving tabular crystals with recurring reentrant angles in the prism zone." — Ford, 1912

Bournonite

"Orthohombric. Crystals usually short prismatic to tabular. Sometimes quite complex with many prism,…

"This consists of four faces perpendicular to the vertical axis." -The Encyclopedia Britannica 1910

Brachy-prism and Macro-pinacoid

"This consists of four faces perpendicular to the vertical axis." -The Encyclopedia Britannica 1910

Bronzite diabase, showing lath-shaped plagioclase crystals.

Bronzite Diabase

Bronzite diabase, showing lath-shaped plagioclase crystals.

Brookite.

Brookite

Brookite.

"The only orthorhombic mineral of importance belonging to the hemimorphic class is calamine. When its crystals are doubly terminated they show different forms at either end of the vertical axis." — Ford, 1912

Calamine

"The only orthorhombic mineral of importance belonging to the hemimorphic class is calamine. When its…

"Orthohombic, hemimorphic. Crystals usually tabular parallel to the brachypinacoid. They show prism faces and are terminated above usually by a combination of macrodomes and brachydomes and base, and below by a pyramid." — Ford, 1912

Calamine

"Orthohombic, hemimorphic. Crystals usually tabular parallel to the brachypinacoid. They show prism…

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals of which the length may be ten or more times as great as the width." —The Encyclopedia Britannica, 1903

Calc-spar

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals of which the length may be ten…

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals." —The Encyclopedia Britannica, 1903

Calc-spar

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals." —The Encyclopedia Britannica,…

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals." —The Encyclopedia Britannica, 1903

Calc-spar

"Calc-spar occurs at a Scottish locality in acicular pyramidal crystals." —The Encyclopedia Britannica,…

Calcite

Calcite

Calcite

Calcite

Calcite

Calcite

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

Calcite.

Calcite

Calcite.

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different forms have been described." — Ford, 1912

Calcite

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different forms have been described." — Ford, 1912

Calcite

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different forms have been described." — Ford, 1912

Calcite

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different forms have been described." — Ford, 1912

Calcite

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different forms have been described." — Ford, 1912

Calcite

"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…