Background. Mineralization is a chemical process that supervenes on specific environmental conditions. Conditions in tissues of the human body foster the creation of different sorts of crystalline phases. The aim of this research was to indicate the mineral composition of carotid sclerosis lodgement in a group of patients in which critical narrowing of carotids reducing blood vessel lumen by 75–80% was diagnosed.

Material and methods. The material for the research was retrieved from 43–71-year-old patients, 6 women (average age: 67 years) and 20 men (average age: 61.3 years). All of them had atheromatosis. The patients were qualified to operation of thromboendarterectomy methodology. In 13 of 26 samples mineral grains were observed. The examination was conducted with a Scanning Microscope (SEM) coupled with an Energy Dispersive Spectroscope (EDS), X-ray Diffraction Analysis (XRD), and Infrared Absorption Spectroscopy (IR).

Results. Mineral grains were observed in 13 of 26 samples. Scanning microscope observations allowed us to ascertain that the mineralization of carotids manifest itself in the form of mineral-organic agglomerations. Chemical analyses that were carried out in the EDS system proved the existence of calcium and phosphate in sclerosis lodgement. X-ray diffraction analysis also proved that the sclerosis lodgement contained phosphates represented by hydroxyapatite and fluoroapatite. Spectra obtained from examinations of samples carried out by infrared absorption spectroscopy indicated PO43– group existence, organic material, and hydroxyl groups. Organic material from the examined samples is represented by phospholipids and cholesterol. The performed analyses prove that wide waves coming from hydroxyl complexes can originate from OH–ions as well as from H₂O particles.

Conclusions. The inorganic phase of the sclerosis lodgement is composed of calcium phosphate, while the organic phase is composed mainly of cholesterol. Research suggests that both organic and inorganic mineralization is created primarily at locations of biological structure damage. Patients with critical structures, who necessitate surgical treatment, are dominated by “soft” and fibrous atherosclerotic plaques with low content of non-organic mineralization.