Carbonatelor

Carbonatelor is a proposed carbonate mineral and a member of a hypothetical class of layered carbonates. First described in the early 2000s by researchers studying high-pressure carbonates, carbonatelor remains a subject of theoretical and limited empirical investigation. The term reflects its carbonate composition and a proposed layered crystal structure that distinguishes it from more common carbonates such as calcite and dolomite.

Its chemical composition is variable, typically represented as (Ca,Mg,Fe,Mn)CO3 with cation ordering that creates alternating carbonate and cation-rich layers. Idealized formulations resemble dolomite in stoichiometry but differ in structure, being predicted to crystallize in a rhombohedral system with a distinct layering along the c axis. Natural occurrence is reported only in select high-pressure metamorphic rock samples and experimental synthesites.

Carbonatelor is associated with ultrahigh-pressure metamorphism and subduction-zone processes. It is thought to form by rearrangement of existing carbonates under pressures above ~2–3 GPa and at elevated temperatures, often in the presence of silicate minerals. Its occurrence can be transient in nature, with samples later transforming into more stable carbonate phases upon pressure release.

Physical properties reported in laboratory studies include a hardness near 3.5–4 on the Mohs scale, a bright to pale vitreous luster, and a weak laboratory acid reaction. In research, carbonatelor is of interest as a potential geobarometer and as a marker for high-pressure carbonate mineralogy, helping to illuminate subduction-zone processes and mantle-crust interactions.