Hyalozoan

The world: The Hyalozoan world seemed as unfit for life as possible, as the combination of a close orbit around a white star and an extreme greenhouse effect created a surface temperature well above 1200°C. Seasonal duststorms, hanging in the thick atmosphere, can black out the sky for many days. Yet, some sort of entirely solid-state life appared out of a self-catalyzing arrangement of silicon crystals. A good part of the dry surface is carpeted in frost-like growths, and "forests" of huge phototrophic shards are common. There isn't any recognizable movement. All this life seems to be extremely ancient, apparently over twelve billion years old.

The species:
--Body structure: The Hyalozoan body is entirely based on silica, aluminum oxides and other inorganic compounds; they form crystalline and quasicrystalline structures which develop from each other with complex geometrical interactions. Different geometries seem to have the function of tissues: some are better for protection from erosion, some for a faster growth, some to diffuse chemicals throughout the body, and so on. Expansion also occurs around "seeds", i.e. wind-carried grains of sand or irregularities of the ground; since the presence of seeds directly determines the crystalline pattern, evolution has shaped them in such a way that they're more likely to be unaffected by seeds or to take advantage from them.
Note that there isn't a clear distinction between individuals or even species. Such distinctions have been made for clarity, but all life on this world might as well be interpreted as a single, planet-wide superorganism. This description is usually limited to those parts that present consistent patterns of growth, spatial localization and ecological role, but the concept of "species" doesn't seem to apply to crystalline life.
--Metabolism: Some parts of the external surface contain metal-rich molecules that appear to be able to extract energy from sunlight and direct it to useful reactions. Since Hyalozoans use so little energy, this is likely enough to sustain them indefinitely. Particles of silica, metals and other inorganic compounds, carried by the wind or located in the ground, are absorbed in the structure and used to expand it. Transport of matter occurs through cavities, the walls of which are slowly broken down in the direction of movement and rebuilt in the opposite one. Energy seems to be stored for later use as molecular bonds in graphite-like sheets, which can be broken down relatively quickly when necessary.
--Perception: The photosynthetic structures also offer a certain photosensitivity (often concentrated in eye-like growths), while piezoelectric crystals allow tactile sensitivity. "Cords" of conductive material carry energy and information around the body, allowing a certain degree of awareness of the environment and coordinated reactions. Since these processes are all so slow, the Hyalozoan perception of time is thousands of times slower than in humans. According to Ktykkryt scholars, stimulating photosensitive structures with pulses of light corresponding to numeric sequences (such as prime numbers) can induce a Hyalozoan to continue the sequence by producing fast-growing spikes in the following numbers. How exactly Hyalozoans process this information is a mystery. It has been speculated that they're actually able to control some aspect of their growth and decay.
--Reproduction: As said above, the structure grows like a crystal, with a process that might be described as gemmation. Often, fragmentation can occur due to external events, i.e. earthquakes or volcanic eruptions; in this case, the severed parts can grow independently, at least until they reach the parent body and merge with it. In some cases, the "deliberate" release of spores has been observed: tiny particles are encased in brittle material, so that the powerful wind can break them free and carry them even for thousand of kilometers. The new bodies, which appear to have a tendency to merge together, are found scattered around all the planetary structure.

The culture: Despite being referred to as "they", Hyalozoans might be equally described as a single mind spanning thousands of kilometers. However, different regions of the common body appear to behave in markedly different ways and to exchange information with each other, probably because processing information through all the structure before choosing a course of action would be too slow even for them. For this reason, Hyalozoans are usually described as separate entities.
How they see humans: Communication between Hyalozoans and other sophonts is extremely difficult. Since their culture is presumed to be still in disarray from the first contact, they probably haven't yet formed an opinion about humans.