There are a number of well defined POM textures for lamellar phases, e.g. mosaic, coarse mosaic, oily streaks and Maltese crosses. As per some references, it seems that for gel phase, the mosaic texture units are close to each other and give an appearance of the so called 'white birefringent' mosaic. Oily streaks usually arise from imperfections along the bilayers. But how can we clearly distinguish between those various lamellar mesophases from each other using POM technique. Is there any textbook that anyone of you have ever used? What should one mean if oily streaks slowly break down to give mosaic texture on heating?