"Hexagonal-rhombohedral; hemimorphic. Crystals usually prismatic, vertically striated. A triangular prism, with three faces, prominent, which with the tendency of the prism faces to be vertically striated and to round into each other gives the crystals usually a cross section like a spherical triangle. Crystals are commonly terminated by base and low positive and negative rhombohedrons; sometimes scalenohedrons are present. When the crystals are doubly terminated they usually show different forms at the opposite ends of the vertical axis." — Ford, 1912

Tourmaline

"Hexagonal-rhombohedral; hemimorphic. Crystals usually prismatic, vertically striated. A triangular…

"This solid is bounded by twenty-four isosceles triangles, and may be considered as an octahedron with a low triangular pyramid on each of its faces." -The Encyclopedia Britannica 1910

Triakis-octahedron

"This solid is bounded by twenty-four isosceles triangles, and may be considered as an octahedron with…

"The hemihedral form {hkk} of the icositetrahedron; it is bounded by twelve isosceles triangles arranged in threes over the tetrahedron faces." -The Encyclopedia Britannica 1910

Triakis-tetrahedron

"The hemihedral form {hkk} of the icositetrahedron; it is bounded by twelve isosceles triangles arranged…

"...bounded by six isosceles triangles...indices as in the hexagonal bipyramid." -The Encyclopedia Britannica 1910

Trigonal Bipyramid

"...bounded by six isosceles triangles...indices as in the hexagonal bipyramid." -The Encyclopedia Britannica…

"...bounded by six trapezoidal hedra...derivable from the scalenohedron." -The Encyclopedia Britannica 1910

Trigonal Trapezohedron

"...bounded by six trapezoidal hedra...derivable from the scalenohedron." -The Encyclopedia Britannica…

"...the two portions are symmetrical with respect to a plane parallel to the ortho-pinacoid." -The Encyclopedia Britannica 1910

Twinned Crystal of Gypsum

"...the two portions are symmetrical with respect to a plane parallel to the ortho-pinacoid." -The Encyclopedia…

The German urn is a 16th century design made out of cut crystal. It is a small vase with a high foot on the bottom.

German Urn

The German urn is a 16th century design made out of cut crystal. It is a small vase with a high foot…

Vesuvianite.

Vesuvianite

Vesuvianite.

Vesuvianite

Vesuvianite

Vesuvianite

"Tetragonal. Prismatic in habit. Often vertically striated. Common forms are prisms of first and second orders, pyramid of first order and base." — Ford, 1912

Vesuvianite

"Tetragonal. Prismatic in habit. Often vertically striated. Common forms are prisms of first and second…

"Tetragonal. Prismatic in habit. Often vertically striated. Common forms are prisms of first and second orders, pyramid of first order and base." — Ford, 1912

Vesuvianite

"Tetragonal. Prismatic in habit. Often vertically striated. Common forms are prisms of first and second…

"Tetragonal; tripyramidal. Crystals usually prismatic. Prominent forms are prisms of the first and second order, pyramid of first." — Ford, 1912

Wernerite

"Tetragonal; tripyramidal. Crystals usually prismatic. Prominent forms are prisms of the first and second…

"Tetragonal; tripyramidal. Crystals usually prismatic. Prominent forms are prisms of the first and second order, pyramid of first. Rarely shows the faces of the pyramid of the third order." — Ford, 1912

Wernerite

"Tetragonal; tripyramidal. Crystals usually prismatic. Prominent forms are prisms of the first and second…

Zircon.

Zircon

Zircon.

Zircon.

Zircon

Zircon.

Zircon.

Zircon

Zircon.

Zircon.

Zircon

Zircon.

"Tetragonal. Crystals usually show a simple combination of prism and pyramid of the first order. The prism of the second order and a ditetragonal pyramid also at times observed." — Ford, 1912

Zircon

"Tetragonal. Crystals usually show a simple combination of prism and pyramid of the first order. The…

Natural crystal. 3, zircon.

Zircon

Natural crystal. 3, zircon.