Figure 1
From: Structurally Coloured Secondary Particles Composed of Black and White Colloidal Particles

Photographs of the secondary particles.
(a) A secondary particle composed of silica particles 360 nm in diameter viewed under a microscope. (b) A secondary particle composed of silica particles 280 nm in diameter viewed under a microscope. (c) A secondary particle composed of silica particles 360 nm in diameter prepared with the addition of NaCl.