Reflective displays material properties

Opalescence is a pearly or milky internal reflection, most common in white or light-colored minerals such as some opal or moonstone (albite or ortho-clase feldspar). This is also known as adularescence. Like iridescence and play of color, these properties are not consistent within any natural material, and can only be used to describe individual specimens. Some synthetic materials have been created specifically to display these properties and so always show them. 

The word smectic comes form the Greek word anriyua, meaning soap and reflects the mechanical properties displayed by many of these materials. All smectics are layered structures having well-defined interlayer distances. Smectic materials are therefore more ordered than nematic ones and occur at a temperature below that for the nematic phase. A number of smectic phases have been identified. ... 

Rubbers are materials which display elastomeric properties, i.e. they can be stretched easily to high extensions and will spring back rapidly when the stress is released. This extremely important and useful property is a reflection of the molecular structure of the polymer which consists of a lightly cross-linked macromolecular network. The molecules slide past each other on deformation, but the cross-links prevent permanent flow and the molecules spring back to their original position on removal of the... 

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