Dazzling technical achievement from North Korea:
Pyongyang, January 8 (KCNA) -- Pyongyang University of Printing Engineering in the Democratic People's Republic of Korea has invented a new technology to make various kinds of colored stones. The colored stones are made by the method of percolating certain colorless liquid of 15-20 percent concentration 5 to 10 mm deep into granite stones in a chemical way in 200 degrees centigrade. The color varies according to the amount of the percolated liquid.
The artificially colored stones are little different from natural ones.
They can be preserved for more than 100 years because of their chemical stability and strong resistance to water and weather.
They are attracting deep interest of building stone producers for the simple production process and low production cost.
That certainly is impressive, but we here in the West have developed countermeasures that can change stone (or brick, or concrete) to many different colors, often several times the same night.
Let a thousand taggers bloom.