They are usually built of crystals of guanine or other reflective biological material, although many other means of reflecting light also exist; see Land and Nilsson (2002) for other examples and a very readable account of mirrors in eyes.
Bill de Blasio's runaway success in the polls as a candidate for mayor of New York City was built on crystal-clear convictions, uncompromising stands and black-and-white promises unburdened by the messiness of governing.
An Associated Press story, which appeared the week after the theft, pegged the stolen collection's value at $5 million and mentioned the most famous of the missing watches only in passing, describing it as built of "gold, crystal and glass".
Consequently, MndBi3_10y is built of four main types of crystals: crystal type 1 is a phyllomanganate, whereas crystal type 4 locally has a tectomanganate-like structure.
These calculations suggested that crystals built of triangular subunits, each made of four hexagonal carbon rings, would have a large surface area and yet be relatively easy to synthesize.
Crystal type 3 had lath-like morphology, with its long distance in the ab plane (20 150 nm) up to ~5 10 times larger than crystal type 2. It was also typically 2 10 times wider, and interference fringes were frequently disrupted, as if it was built of aggregated type 2 crystals (Fig. 9).
Lamellar network built of parent and daughter crystal also appears in this region, where daughter crystallization is commonly frustrated under such strong flow.
As a solution that satisfies these constraints, I put forward an evolutionary scenario in which life on Earth emerged, powered by solar irradiation, within porous edifices of hydrothermal origin that were built of photosynthesizing zinc sulfide (ZnS) crystals, in the "Zn world".
Finally, crystal type 4, built of lath-like units rotated by n × 120° (n being equal to 1 or 2), results from stacking of crystal type 3.
Nan Madol was built of huge, heavy logs carved out of basalt crystal.
