tautoclin

tautoclin Min.

(ˈtɔːtəʊklɪn)

[ad. Ger. tautoklin (Breithaupt 1830), f. Gr. ταὐτό (tauto-) + κλίνειν to bend, incline; so called ‘because it has the same rhombohedral angle as dolomite’ (Chester).]

A greyish-white variety of ankerite.

Dana Min. (ed. 5) 685.