A single-crystal diamond having a first facet plane is prepared. The single-crystal diamond is fixed to the support based on the first facet plane. An X-ray image of the single-crystal diamond is captured, the X-ray image being an X-ray image in which a crystal orientation of the single-crystal diamond is associated with an X-ray emission direction by associating the support to which the single-crystal diamond is fixed with the X-ray emission direction. A position of an inclusion of the single-crystal diamond in the single-crystal diamond is specified based on the X-ray image. It is determined whether or not a shape of the diamond tool intermediate is extractable from the single-crystal diamond with the inclusion being not included in an inclusion-excluded region. The shape of the diamond tool intermediate is extracted from the single-crystal diamond with the inclusion being not included in the inclusion-excluded region.

A polycrystalline super hard construction is disclosed having a first region comprising a body of thermally stable polycrystalline super hard material having an exposed surface forming a working surface, and a peripheral side edge, the polycrystalline super hard material comprising a plurality of grains of super hard material; a second region forming a substrate to the first region; and a third region interposed between the first and second regions. The third region extends across a surface of the second region along an interface, the interface comprising a portion having an uneven topology and a substantially planar portion, the third region comprising a composite material including a first phase comprising a plurality of non-intergrown diamond grains, and a matrix material.

A single-crystal diamond cutting tool is provided with a flank and a rake face, a cutting edge being provided at a boundary between the flank and the rake face, an inclined surface being provided at a location distant from the cutting edge, the inclined surface being contiguous to the rake face and inclined at 0.05 degrees or more and 80 degrees or less with respect to the rake face, the rake face having a roughness Ra of 1 .Math.m or less, the cutting edge being provided with a chamfered surface or round honing having a width of 1 .Math.m or less, the cutting edge having projections and depressions having a width of 100 nm or less and smaller than that of the chamfered surface or round honing.

A single-crystal diamond cutting tool is provided with a flank and a rake face, a cutting edge being provided at a boundary between the flank and the rake face, an inclined surface being provided at a location distant from the cutting edge, the inclined surface being contiguous to the rake face and inclined at 0.05 degrees or more and 80 degrees or less with respect to the rake face, the rake face having a roughness Ra of 1 .Math.m or less, the cutting edge being provided with a chamfered surface or round honing having a width of 1 .Math.m or less, the cutting edge having projections and depressions having a width of 100 nm or less and smaller than that of the chamfered surface or round honing.

A diamond tool includes a diamond at least on a cutting edge including one or two or more diamond grains including a diamond phase composed of a diamond crystal structure and a graphite phase composed of a graphite crystal structure. When a ratio I.sub.π*/I.sub.σ* between an intensity of a π* peak derived from a π bond of carbon in the graphite phase and an intensity of a σ* peak derived from a σ bond of carbon in the graphite phase and a σ bond of carbon in the diamond phase is determined for the diamond grain by measuring an energy loss associated with excitation of K-shell electrons of carbon by electron energy loss spectroscopy, the ratio I.sub.π*/I.sub.σ* of the diamond grain on a surface of the cutting edge is 0.1 to 2 and a ratio I.sub.π*/I.sub.σ* of the diamond grain at a depth position of 0.5 μm from the surface of the cutting edge is 0.001 to 0.1.

A diamond tool includes a diamond at least on a cutting edge including one or two or more diamond grains including a diamond phase composed of a diamond crystal structure and a graphite phase composed of a graphite crystal structure. When a ratio I.sub.π*/I.sub.σ* between an intensity of a π* peak derived from a π bond of carbon in the graphite phase and an intensity of a σ* peak derived from a σ bond of carbon in the graphite phase and a σ bond of carbon in the diamond phase is determined for the diamond grain by measuring an energy loss associated with excitation of K-shell electrons of carbon by electron energy loss spectroscopy, the ratio I.sub.π*/I.sub.σ* of the diamond grain on a surface of the cutting edge is 0.1 to 2 and a ratio I.sub.π*/I.sub.σ* of the diamond grain at a depth position of 0.5 μm from the surface of the cutting edge is 0.001 to 0.1.

Provided is a synthetic single crystal diamond containing nitrogen atoms at a concentration of more than 600 ppm and 1500 ppm or less. The Raman shift λ′ (cm.sup.−1) of a peak in a primary Raman scattering spectrum of the synthetic single crystal diamond and the Raman shift λ (cm.sup.−1) of a peak in a primary Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a content of 1 ppm or less satisfy the following expression (1):
λ′−λ≥−0.10  (1).

A tool of the present disclosure includes a tip end portion. The tip end portion has a surface. At least a part of the surface includes a plurality of protrusions, a first recess provided by contact between ends of two adjacent protrusions of the protrusions, and a second recess different from the first recess. The second recess is provided inside at least one of the protrusions or provided to extend across the two adjacent protrusions.

A method for producing a freeform Fresnel surface having a number of Fresnel facets with a respective Fresnel segment surface and a trailing edge includes the production of the freeform Fresnel surface via machining processing of a starting body based on the construction data for the freeform Fresnel surface. With the aid of the circular cylinder casing surfaces and/or cone casing surfaces, the projection of the edges of the Fresnel facets on the x-y-plane represent circular paths for the creation of the construction data.

A method for producing a freeform Fresnel surface having a number of Fresnel facets with a respective Fresnel segment surface and a trailing edge includes the production of the freeform Fresnel surface via machining processing of a starting body based on the construction data for the freeform Fresnel surface. With the aid of the circular cylinder casing surfaces and/or cone casing surfaces, the projection of the edges of the Fresnel facets on the x-y-plane represent circular paths for the creation of the construction data.