Abrasive stick and polishing method

An abrasive stick in a rod shape having a distal end portion pressed against a surface to be polished of a workpiece to polish the surface to be polished, the abrasive stick comprising:

• a plurality of inorganic filaments extending in an axial direction;
• and a resin impregnating the inorganic filaments and solidified, wherein
• cross sections of the inorganic filaments are exposed on a distal end surface of the abrasive stick,
• the abrasive stick has elasticity to flex in a direction intersecting the axial direction,
• the inorganic filaments comprise 80 to 90% by weight of an alumina component and 20 to 10% by weight of a silica component,
• the inorganic filaments have a crystal structure including mullite crystals and intermediate alumina,
• the mullite crystals have an average grain size smaller than 25 nm,
• a peak of a diffraction line of a (110) plane of mullite appears in a diffraction chart obtained by irradiating the inorganic filaments with X-rays, and
• the average grain size of the mullite crystals is calculated by the following formula based on the diffraction chart:
• D
• hkl
• =
• 0.9
• λ
• β
• 1
• 2
• ·
• cos
• ⁢
• θ
• [
• Math
• .
• 1
• ]
• Dhkl:
• an average grain size of a (210) plane
• λ:
• a wavelength of X-rays
• θ:
• a glancing angle of X-rays
• β1/2:
• a full width at half maximum of a diffraction line of the (210) plane of mullite in which a crystal structure 2θ by X-ray diffraction appears near 26°.