"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

This crystal of Calcium Phosphate, Apatite, represents a complex combination of hexagonal hemihedral forms produced by the pyramidal selection. The nine forms comprise the basal pinacoid ,(P); the prism of the first order, (M); second order, (u); and third order, (h); three pyramids of the first order, (r), (x), and (y); one pyramid of the second order, (s); and one of the third order, (m).

Calcium Phosphate, Apatite

This crystal of Calcium Phosphate, Apatite, represents a complex combination of hexagonal hemihedral…

Combination of holohedral tetragonal forms.

Combination of Tetragonal Prism and Basal Pinacoid

Combination of holohedral tetragonal forms.

A beryl crystal, an example of a basal pinacoid.

Beryl crystal

A beryl crystal, an example of a basal pinacoid.

A beryl crystal, an example of a basal pinacoid.

Beryl crystal

A beryl crystal, an example of a basal pinacoid.

A beryl crystal, an example of a basal pinacoid.

Beryl crystal

A beryl crystal, an example of a basal pinacoid.

"...shows a combination of a hexagonal prism (m) with the basal pinacoid (c)." -The Encyclopedia Britannica 1910

Hexagonal Prism and Basal Pinacoid

"...shows a combination of a hexagonal prism (m) with the basal pinacoid (c)." -The Encyclopedia Britannica…

This form shows the planes given on a crystal of hydrous nickel sulphate: the basal pinacoid, (c); three pyramids of the second order, (m), (o), and (q); two pyramids of the first order, (n) and (p); and the prisms of the first and second orders, (r) and (s).

Hydrous Nickel Sulphate

This form shows the planes given on a crystal of hydrous nickel sulphate: the basal pinacoid, (c); three…

"This consists of four faces parallel to the brachy axis." -The Encyclopedia Britannica 1910

Macro-prism and Brachy-pinacoid

"This consists of four faces parallel to the brachy axis." -The Encyclopedia Britannica 1910

This is an orthorhombic crystal of olivine. It is formed by the orthorhombic prism in combination with two pinacoids.

Orthorhombic Crystal of Olivine

This is an orthorhombic crystal of olivine. It is formed by the orthorhombic prism in combination with…

This form shows the fundamental prism (p) on a crystal of topaz, in combination with another prism, (p'); the basal pinacoid, (c); the brachydome, (g); and the four pyramids, (o), (o'), (o''), and (x).

Orthorhombic Crystal of Topaz

This form shows the fundamental prism (p) on a crystal of topaz, in combination with another prism,…

Holohedral orthorhombic combination

Prism and Basal Pinacoid

Holohedral orthorhombic combination

This form shows a very complex combination of thirteen tetragonal forms occuring on the mineral Vesuvianite: the prism of the first order, (d); prism of the second order, (M); basal pinacoid, (s); three pyramids of the first order, (c), (b), and (u); the ditetragonal prism (f); and the four ditetragonal pyramids (z), (x), (e), and (a).

Vesuvianite

This form shows a very complex combination of thirteen tetragonal forms occuring on the mineral Vesuvianite:…

Also known as Fergusonite, this crystal shows the basal pinacoid, (c); the unit pyramid, (s); and the pyramid and prism of the third order, (z) and (r) respectively.

Yttrium Niobate

Also known as Fergusonite, this crystal shows the basal pinacoid, (c); the unit pyramid, (s); and the…

"A crystal of zincite with a prism terminated by a pyramid above a basal pinacoid below." — Ford, 1912

Zincite

"A crystal of zincite with a prism terminated by a pyramid above a basal pinacoid below." — Ford,…