Dims: 2.24x1.42x0.55" (5.7x3.6x1.4cm)
Wt: 1.52oz (43.0g)
Groix Island, France
This is a heavily intergrown mass of muscovite and glaucophane crystals. Most of the mass is dark blue glaucophane, but most of the surface is a dirty greenish-yellow muscovite. The glaucophane looks dark gray to black in the bulk, but examination with bright lights and a loupe shows many cleavage planes and some isolated crystals which are somewhat translucent and blue, the same blue as vivianite, but darker. This material is very flaky, and thin fragments also show this color. Still, the bulk of the glaucophane just looks black.