Yeatmanite, (Mn, Zn)16Sb2Si4O29, is a new mineral from Franklin, N.J. It is triclinic, pseudo-orthorhombic, with multiple twinning on b(010) and macroscopic twinning on (023). Elements (x-ray): a:b:c = 0.7811:1:0.4775. α=103°49′; α=101°45′; γ = 87 12′. Cleavage perfect ‖(100); H. 4, G. 5.02 ± .10. Biaxial, negative; X near a[100], Y near b[010], ZΛc[001] = 3½°. Indices (Na): nX= 1.873, nY = 1.905, nZ= 1.910, all α0.003. 2V about 49°, r<v, dispersion moderate. Clove-brown crystalline plates embedded in willemite. The composition of sarkinite, associated with the yeatmanite, differs from the Langban material only in having 5.38 per cent of zinc.

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