Cyrilovite

Cyrilovite can be identified by its hardness of 4 on the Mohs scale, Bright yellow color. Look for these key characteristics when examining specimens.

Cyrilovite typically appears in Bright yellow, honey-yellow, orange to brownish yellow, brown. Color can vary depending on impurities and formation conditions.

Cyrilovite has a hardness of 4 on the Mohs scale. This gives it moderate hardness.

Cyrilovite is a vitreous translucent mineral that can appear in colors ranging from a bright yellow, honey-yellow, orange to brownish yellow, or brown and it has a hardness of 4. It has a yellow streak. The mineral is classified under the space group P41212 and is tetragonal.

The chemical formula of cyrilovite is NaFe3(PO4)2(OH)4·2(H2O). Parent phosphate minerals, fluorapatite and triplite-zwieselite, were transformed by hydrothermal alteration and weathering to give a complex, microcrystalline intergrowth of secondary phosphate minerals that include cyrilovite. The sequence of phosphate transformations ended with the formation of cyrilovite within the fluorapatite fractures and the replacement of fluorapatite by lipscombite and crandallite-group minerals. Fransolet suggest that a part of the leached Na leads to the precipitation of cyrilovite, in the fissures cause by the volume decrease resulting from the transformation of typhylite to heteresoite. Mobilization of alkalis and of relatively immobile elements including aluminium and rare-earth elements are subsequently incorporated into precipitating cyrilovite, lipscombite and crandallite-group minerals. The chemical analysis shows substitution not only of Al for Fe, but also of K and Mn for Na, measured and observed specific gravities are considered to be in good agreement. Ferric iron occurs virtually alone in H20 rich minerals such as phosphosiderite, and coupled with Na, K, or Ca in cyrilovite. It is soluble in hot dilute HCl, in hot dilute H2SO4, and, with difficulty, in hot dilute HNO3. In the closed tube, it gives off water and fuses.