Translucent concrete

[blobrana]

Hum,
So you thought only Superman who could see through concrete walls, but an exhibit at the National Building Museum shows you can do it too.

Called "Liquid Stone," the show features translucent concrete.

One display is a wall of translucent concrete blocks. When someone stands in front of it and light is shone from behind, the person's shadow can be seen clearly on the other side.

 :-o

[blobrana]

Er,
That would be called sapphire?
(Aluminium oxide or alumina, occurs naturally as ruby, sapphire)

Aluminium  is a bit like silicon; and i imagine that i could make a Al-Si-O crystalline lattice compound that would be very strong and  yet quite transparent...

 :-)

[blobrana]

hum,
i found a related article:
" Casio has announced the development of a new lens for compact cameras which is made from a transparent ceramic material instead of glass.
The material (Lumicera) was originally developed for other applications but happened to have interesting optical properties including a higher refractive index than glass. Casio has refined the process of polishing and coating the material to make lenses which can be thinner and stronger than conventional glass."

Article here.

[blobrana]

Errm....

Strangly,
As a follow-up to making a Al-Si-O crystalline lattice compound, scientists in the US have developed a novel technique to make bulk quantities of glass from alumina for the first time.
Anatoly Rosenflanz and colleagues at 3M in Minnesota used a "flame-spray" technique to alloy alumina (aluminium oxide) with rare-earth metal oxides to produce strong glass with good optical properties.

The method avoids many of the problems encountered in conventional glass forming and could, say the team, be extended to other oxides .