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Deep within the violent Jovian atmosphere towering water and ammonium hydrosulfide clouds are lit by lightning bolts and weak sunlight gleaming through a high layer of cirrus clouds of ammonia crystals. Ammonia crystals refract and reflect the sunlight to surround the sun with exotic halos.  Painting by illustrator and author Ron Miller, he used HaloSim3 to simulate the NH3 halos (large view). ©Ron Miller, reproduced with permission.
Clouds and temperatures in Jupiter's atmosphere. 

The upper ammonia crystal clouds are likely tiny cubes, octahedra and cuboctahedra and could form halos similar to those predicted for CO2 clouds on Mars.
The highest clouds in mighty Jupiter's hydrogen/helium atmosphere are a cirrus like layer of ammonia (NH3) crystals where the pressure is 0.3 - 0.7 bar and temperatures about -110 C. Solid ammonia has a cubic symmetry structure and thus could form cloud crystals of similar forms to those of cubic CO2. Ammonia has a slightly greater refractive index than CO2 and is transparent. Halos from the upper Jovian clouds could therefore be very similar indeed to those predicted for tiny Mars.

20-30 km deeper there are clouds formed from ammonium hydrosulfide crystals. They are probably darkened and coloured by sulfurous or phosphorus polymers and organic compounds. Not enough is known to predict their halos.

60 km beneath the ammonia cloud layer we find superficially Earthlike clouds of water molecules. Pressures are 5-6 bar and temperatures are similar to those of Earth. Their windblown anvils and cirrus push high into the hydrosulfide layer and their ice crystals could form Earthlike halos. Their lower levels have liquid droplets and rain or drizzle warm corrosive ammonium hydroxide solution down into the depths.

In summary, Jupiter's high ammonia cloud layer could form halos from its octahedral, cuboctahedral or even rhombic dodecahedral crystals like those predicted for CO2 clouds on Mars . Much deeper, when the weak sun penetrates through, water-ice cirrus might give glimpses of Earthlike halos.