"...take any three edges formed by the intersection of three faces of a crystal. These axes are called…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

Cubes of Iron Pyrites frequently show a striation of their planes in one direction, which is perpendicular…

Represents the combination of an octrahedron and a cube, with the cube faces predominate.

Represents the combination of a cube and an octahedron, with both faces being equal.

This crystal of Aragonite shows a method of twinning where the twinning plane may change its direction,…

"Monoclinic. Habit varied. Crystals usually nearly equidimensional in the three axial directions and…

"This is the hemihedral form of the triakis-octahedron; it has the indices {hhk} and is bounded by tweleve…

The diamond is cut to show the stone's brilliance, creating different parts to the cut: table, crown,…

Various types of square cut diamonds. Top row: Old square cut diamonds. Bottom row: English square cut…

"...bounded by twenty-four scalene triangles...This form may be considered as a combination of two scalenohedra,…

Diopside is a monoclinic pyroxene mineral with composition MgCaSi2O6. It forms complete solid solution…

Crystal; This form is a combination of an icositetrahedron and a rhombic dodecahedron, where the faces…

Crystal; This form is a combination of an icositetrahedron and a rhombic dodecahedron, where the faces…

"Hexagonal-rhombohedral. Crystals are usually the unit rhombohedron (cleavage rhombohedron). Faces often…

"This is the hemihedral form of the hexakis-octahedron and has the indicies {hkl}; it is bounded by…

"...shows two crystals of tartaric acid, a a right-handed crystal of dextro-tartaric acid, and b a left-handed…

"Monoclinic. Crystals are often much elongated parallel to the ortho-axis with a prominent development…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

"Isometric. Common forms dodecahedron amd trapezohedron, often in combination. Hexoctahedron observed…

"Here the plane of projection is tangent to the sphere, and normals to all the faces are drawn fro mthe…

Gold crystals of the form 3O3, {311}, sometimes resemble combinations of the rhombohedron and scalenohedron.

"The second form of carbon, known as graphite, is a leaden-gray solid with a metallic luster and a specific…

Certain crystals of green fluorspar from Saxony, showing the form ∞ 03, {310}, have one half of their…

"Monoclinic. Crystals usually tabular parallel to clinopinacoid; in diamond-shaped crystals with edges…

"Monoclinic. Crystals usually tabular parallel to clinopinacoid; in diamond-shaped crystals with edges…

This image represents a twin of the monoclinic mineral Gypsum. Its twinning plane is the orthopinacoid.

"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…

"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…

"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…

Hemimorphism in the direction of the vertical axis has been observed on crystals of the tetragonal salt,…

"...bounded by twelve isosceles trianes each of which are equally inclined to two planes of symmetry."…

"Here each face of the octahedron is replaced by six scalene triangles, so that altogether there are…

"The hemihedral form {hkl} of the hexakis-octahedron; it is bounded by twenty-four scalene triangles…

This form is bounded by forty-eight similar scalene triangles. Its solid angles are of three kinds:…

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

This figure exhibits a combination occurring on the ferro-magnesian meta-silicate, Hypersthene. Forms:…

"Bounded by twenty-four trapezoidal faces, and hence somethings called a 'trapezohedron.'" -The Encyclopedia…

Also known as Stolzite, this crystal is bounded by the unit pyramid of the first order, P, {111} (o),…

Crystal; If the alternate planes of the hexoctahedron extend until the intersect, a new for will result.…

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

"Isometric. Octahedral habit, sometimes twinned octahedrons. Dodecahedron at times, either alone or…

As shown on this crystal of Magnetite, the octohedron, by the crowding out of two of its opposite faces,…

The most common twinning plane is the orthopinacoid ∞P∞̄ , {100}, as may be seen in this example…

"Five kinds of glass are made: flint glass, or crystal; crown glass, broad sheet glass, bottle, or green…