Millions of years ago, the world was covered in continents humans never saw and seas we never swam. One of these ancient bodies of water came to be called the Tethys Ocean, after a Greek sea goddess and Titaness. Tectonic plates shifted and the waters rearranged, but this ocean left its mark on the land that became Kazakhstan. In the wild west of the country there's a desertous region called Mangyshlak, a geologist's paradise. Strange rock formations abound, and the landscape is so bizarre its defining figures have gotten their own names in the vocabulary of Russian science - rocky escarpments called chinks [чинки; chinky]. On chinks with names like "Penitent Monk" and "Sugarloaf", the marine creatures of the Tethys Sea have lasted to the present day as crusty layers of fossils. The rock that these ancient invertebrates now call home is a subtype of limestone that's hard to identify in English - sometimes it's called cocquina. In Russian, though, the word is quite precise: rakushka [ракушка], which means "seashell."
From 1948-1954, the Kazakh Academy of Sciences started making yearly expeditions from Almaty to Mangyshlak, exploring the possible use of rakushka as a cheap and effective building material. In 1955, mining began with the introduction of the СM-89-A carving machine, and it has continued nearly unabated since. The machines used are really cool; they saw bricks of the stuff right out of the ground, soft and neat like cubes of cheese. Anyways, the sliced-out rakushka was sent to Almaty, where panels of the shelly rock were fastened to hundreds if not thousands of public buildings. I would dare to say that Almaty has more limestone buildings than anywhere else on Earth, and the fossils are so distinctly preserved that it's easy to look at a wall here and imagine a pile of molluscs on the Tethys seabed, animals from eons ago set into the strict facades of Communist headquarters.
Nearly every late-Soviet landmark in Almaty uses rakushka. Like granite rubble, the limestone was used to break up the monotony of concrete, while giving a natural feel to a city framed by mountains. The stone comes in various grades; the lowest-quality seems to consist of nothing but fossils, with less of the calcium deposits that keep it all together. This stone is softer and tends to chip, and it was used in buildings for second-rate bureaucrats and as paving material in parks. The pinkish stone from the Zhetybai field, on the other hand, was especially prized for its natural hue and was used liberally in the Hotel Kazakhstan, the Palace of the Republic, and other monumental projects throughout town. All rakushka, unfortunately, tends to age without much grace, and Almaty now faces a facade crisis, as the old limestone gets grey and grimy but the new facades burn up or fall down.