- Wellcome
Transmitted light
Relief very low, colorless on PPL, cleavage not visible. Tetragonal, pseudo-cubic. Crystals roundish or with 8 sides, 2 generations are possible. Many inclusions are typical. In XPL, very low birefringence (very dark). Always polysynthetic twinning (looks similar to microcline, but is much darker and more irregular.). U(+), may be B(+).
Relief very low. Cubic, in PPL colorless, gray or pale bluish. Euhedral grains, pseudo-hexagonal ou rounded. Cleavage not visible. “Haze” of inclusions in sectors, in the center or at the edges. Typical of alcaline volcanic rocks, associated with nepheline, leucite and sanidine. Easy to confuse with analcime, leucite, sodalite and haüyne.
