This study compares the reactivity of as-received and mechanically activated olivine (Mg0.93Fe0.07)(2)SiO4 (collected from Aheim, Norway) with carbon dioxide at ambient temperature (similar to 25 degrees C) and 60 bar in the absence of any organic or inorganic additives. Mechanical activation (30 min) was performed in a laboratory ball mill. Mineral carbonation (6 h) was performed in a high-pressure laboratory reactor. Various instrumental techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TA) and scanning electron microscopy (SEM) were used to characterise solid products before and after carbonation as well as before and after filtration. Structural, surface and morphological changes of mechanically activated olivine resulted in an increased reactivity. The presence of amorphous magnesium carbonate in the form of hydromagnesite ((MgCO3)(4)center dot Mg(OH)(2)center dot 4H(2)O) has been confirmed. (C) 2013 Elsevier B.V. All rights reserved.