It is easy to see that rains of animals have an artificial origin. It is more difficult when inorganic substances come down in dry form or in water (rain, hail or ice), as it could be possible that this is of cosmic origin. However these kinds of anomalous rains are very strange too. In the 19^th and early 20^th century) these rains were often analyzed by chemists of that time. It didn't shed much light on the mystery due to their limited scientific equipment of that time. At present we have extremely advanced technological equipment of all kind to analyze any substance. Unfortunately, there is not much interest at all from scientists to do this, and samples often get 'lost'. Sometimes it is not worth the expense.

I think it possible that these inorganic materials also come from spaceships cleaning out their cargo areas, tanks, reservoirs, because some of the rains are very strange, and the rains have accompanying characteristics that are exactly the same as with the live animal rains: loud noises, repeating of the strange rain in the same area, light flashes, being limited to a very small area, and happening during heavy rainfalls.

I didn't look up original news reports of these rains, but only list their characteristics, for the purpose of comparison. They are taken from Charles Fort Book of the Damned, and thus well before the military started to experiment on the population with their biological end chemical warfare agents which could account for similar kinds of 'rains' in the second half of the 20^th century.

Powders

• Yellow substance, giving off nitrogen and ammonia and an animal odor.

• A yellow substance. But the microscope revealed numerous globules of cobalt blue, also corpuscles of a pearly color that resembled starch.

• Reddish to yellow substance, it carbonized and spread the odor of charred animal matter that it was not pollen, that in alcohol it left a residue of resinous matter.

• Yellow powder. It had an earthy, insipid taste, and is described as "unctuous." When heated, this matter turned brown, then black, then red.

• A combustible yellowish substance, covering, at least two inches thick, an area of 600 or 700 square feet. It was resinous and yellowish. When torn, it had the tenacity of cotton. When placed in water, it had the consistency of resin. "This resin had the color of amber, was elastic, like India rubber, and smelled like prepared oil mixed with wax."

• Red powder.

 Colored Rains

Red rains, sometimes fluid, sometimes viscous.

Often analyzed by chemists of the time as being water and a (sometimes high) percentage of animal matter. Go figure where that animal matter came from.

• Red rain, estimated that about 10,000,000 tons of matter had fallen in England alone! Other vast quantities in Australia and Russia.

• Red rain; red substance when burned, the odor of animal matter from it was strong and persistent.

• Hailstones, some red, some blue, some whitish.

• Red rain, drops of this rain left stains "such as sandy water could not leave."

• A reddish rain fell copiously for two hours. A second red shower fell at 9 o'clock. Three days later, the red rain fell again. The next day another red rain fell. Each fall occurred in "exactly the same quarter of town."

• Vividly red rain, blood-like.

• A substance like blood, somewhat coagulated.

• Thick, viscous, red matter.

• A highly unpleasant substance, the substance was clear blood and portions of flesh scattered upon tobacco fields.

• A reddish substance that was "thick, viscous, and putrid."

• A rain fall "bringing down with it a red substance, which proved on examination to be a red meal mixed with fine sand."

• A rain of a peach-red color. In this rain were flakes of a hyacinthine tint, said to be organic in nature.

• Red matter that looked like "vegetable cells".

• Red snow.

Black rains were more often than the few description below, as often only the color was mentioned and nothing else.

• Black rain, the color of ink, and of a fetid odor and very disagreeable taste.

• Black rain, it left a most peculiar and disagreeable smell in the air.

• A rain so black as to be described as a "shower of ink."

• After two showers of a black rain: two of these showers, vast quantities of a substance
  described sometimes as "pumice stone," but sometimes as "slag, "were washed upon the sea coast" near Slains (Scotland).

• A black rain, so intense that the following day brooks were still dyed with it.

• A black rain was accompanied by "shocks like those of an earthquake." The earthquake had occurred at the climax of intense darkness and the fall of black rain.

Gelatinous Substances

Often found to be of a gelatinous or similar texture, but rarely analyzed. Interestingly, in several cases luminous bodies were seen in the sky prior to the gelatinous falls.

• Grayish substance: nut sized masses of a substance that is described as both resinous and gelatinous. It was odorless until burned: then it spread a very pronounced sweetish odor. It is described as like gelatin, but much firmer: but, having been in water 24 hours, it swelled out,
  and looked altogether gelatinous.

• The ground was found covered with masses of jelly, the size of peas.

• A storm of glutinous drops neither jelly fish nor masses of frog spawn. "Many soon developed into a wormlike chrysalis, about an inch in length." A scientist examined it and said it to be "minute worms in filmy envelopes". It repeated itself several days later.

• "Lumps of jelly" were found on the ground. The substance was whitish, or resembled the coagulated white of an egg.

Greasy Stuff

• Showers of a sort of matter like butter or grease, having "a very stinking smell."

• A substance which the country people called "butter". "soft, clammy, and of a dark yellow" that cattle fed "indifferently" in fields where this substance lay. "It fell in lumps as big as the end of one's finger." It had a "strong ill scent." His Grace calls it a "stinking dew."

• A substance that was wine yellow, transparent, soft, and smelling like rancid oil.

• A fall of oily, reddish substance.

• Hail in which was a substance described as 'turpentine'.

Other Inorganic Substances

• A fall of of a mass of burning sulphur, about the size of a man's fist.

• Large crystals of salt fell in a hail storm.

• Saltish substance in a form like snow.

• Substance that looked like crystallized nitre, and that tasted like sugar

• Several falls of what looked like slag or cinders, or resembling coke, and burning, bituminous matter", and carbonaceous matter, substances resembling coal.

• Interesting account: "On June 15, 1857 a farmer who lived in Ottawa, Illinois reported that he heard a hissing sound in the sky and he looked up to see a shower of cinders falling to the earth. They landed on the ground in a V-shaped pattern about 50 feet from where he was standing and caused the ground to steam and the grass to catch fire. The larger cinders buried themselves into the earth and even the smallest pieces were inserted into the ground at least partially. The farmer, whose name was Bradley, noticed a small, dense and dark cloud “hanging over the garden” at the time of the fall. The weather that day had been damp and a little rainy but no thunder or lightning had been reported. "

Strange Ice Blocks

Always during heavy thunderstorms, but they cannot have formed as hailstones do.

• Falls of large amounts of large ice masses, the size of 'man's head, pumpkin size, many inches in diameter, many pounds etc. In one instance killing thousands of sheep.

• Singular blocks of ice, many pounds each, many feet thick! "80 pounds", "a cubic yard in size". "the size of a sheep"

• Cases had been reported in China and Brazil in 1995 where blocks as heavy as 440 pounds crashed to Earth.

• In 1849, a block of ice that was estimated to weigh a half a ton fell on the Balvullich farm in Ord, Scotland. It measured about 20 feet in diameter and was reported to be crystal clear, although apparently made up of many cubes and diamond-shaped hunks of ice fused together.

• Flat pieces of ice fallen in clear weather, but thunder sounds were heard. Flat pieces of ice, an inch long, after a "profound darkness". Roughly broken fragments of a smooth sheet of ice. two inches long, one inch thick.

• Ice pieces that resembled icicles.

• Small hailstones that exploded.

Some interesting accounts of blue colored ice blocks in Greece (from https://web.archive.org/web/20141010002845/http://www.vembos.gr/forteanfalls.htm ):

• “Blue Ice” Mysteries : Late in November, 1981, Mrs. Androniki Maglara in Poros, Argolis, Peloponnese, heard a loud bang οn her rooftop. Upon examination, she saw a block of "blue ice" the size of a human fist. "At first," she said, "Ι thought they were pieces from my solar heater and Ι called a technician who explained that the 'blue ice' had nothing to do with the heater. Then Ι worried, and Ι called the police. Ι kept one of these things in the refrigerator. What are they?" The police, after a field investigation, didn't seem to be interested in the curious incident. A chemist friend of Mrs. Maglara performed some simple experiments, but couldn't determine the composition of the "blue ice." Also, it was certified that the rooftop had blue stains that proved to be indelible. Apparently they were caused by the blue ice chunks melting. The piece that was found by Mrs. Maglara was kept in the refrigerator and later was said to be brought to Athens for a full scientific examination, but nobody knows for sure what finally happened to it. (Source:Apogevmatini, 26 November 1981).

  On June 16, 1985, in Demiri village, near Tripolis of Arcadia, in central Peloponnese, a strange object falling with tremendous speed and emitting a whistling sound as it was coming down hit a hangar belonging to Konstantinos Nikolopoulos. The sound of the impact terrified Nikolopoulos and his friends Konstantinos Dimopoulos and Demetrios Dalamangas, who were sitting together chatting in the yard of the house. The object must have been enormous, since even after shattering οn impact, the largest piece was the size of a watermelon! The collision was so hard that a great hole was made in the hangar, and one of the thick, wooden, support beams was broken like a match. The three men approached the fallen debris and discovered that it was blue in color (like the object of Poros, four years earlier). Suddenly, a few minutes after the fall, the debris started to melt at a faster speed than that of normal water-composed ice. Its smell was undefinable, and it was not toxic οr corrosive. They touched the pieces and found that their hands were colored blue. The biggest piece of ice was put into the refrigerator.

  The next day, a Greek Air Force helicopter arrived at the scene, carrying Col. Andreas Varrenis, two other officers, and two scientists. They examined the chunk that was left, which had been carried to the police station by Mr.Nikolopoulos the day before. The first test was for radioactivity. The conclusion was that the "ice" was not radioactive. The officers took the object into the helicopter and left, carrying the "ice" to the Ministry of National Defense. On June 18th, the Minister of Defense, Antonis Drosoyannis, told reporters that the object was something unexplained and that it had to be sent for further analysis and research either to the Democritus Center for Nuclear Research οτ to the General Chemistry of the State. What finally happened remains a mystery. (Source: Apogevmatini, 18 June 1985; Ethnos, same date; Nea, same date).

[my own note: ice must have been water with a blue dye or solvent in it before it froze. Also, why does the military retrieve an ice block?]