# The afternoon it rained stones in Transylvania

*Mociu, near Cluj · Friday 3 February 1882 · 3:45 pm*

A fireball crossed the sky over Cluj, and thousands of stones fell on the snow round Mociu, a village about 34 kilometres east of Cluj-Napoca: small ones at one end of the field, giants at the other. Below, they fall again on the map drawn at the time by the professor who gathered them. And the “56 kg stone” in the books turns out to be 102 stones weighed together.

## How the Mociu stone shower fell

### 3:45 pm. A fireball in daylight

From Cluj, many people watch a brilliant fireball cross the sky, roughly from north-west to south-east. Behind it trails a long, narrow band of greyish-white smoke. Only those looking at that very moment see at its tip a ball of fire with a violet tinge, shooting forward.

At the edge of the wood towards Vișea, the forest guard Cristuran Juon sees a dazzling flame as thick as an arm coming from Botos hill, throwing off sparks. He calls it a fiery dragon. The arrow Koch drew for the direction the stones came from starts near Bonțida.

### Three bangs above the village

At Coasta, a young man, Godulan Victor, is watching from a high spot with a clear view to the north-west. He sees a shining greyish-white cloud, the size of a cartwheel, that seems to stand still above the village. Three loud bangs follow, and the cloud bursts apart in every direction. Then comes a rattle like gunfire and finally a hum like wind, though there is no wind at all.

Koch was sure the hum was made by the countless falling stones. In Cluj the detonations arrive about three minutes after the fireball, deep and long, and set windows shaking.

### At one end, the small ones

At the north-western end, round Coasta and Vișea, the stones fall thickest and smallest, onto a thin layer of snow.

At Vișea, one the size of a pigeon's egg lands in the middle of the villagers and, luckily, hits nobody. Another lands on a widow's house; she picks it up and finds it warm.

### Then bigger, and rarer

Further south-east, round Bărăi, Vaida-Cămăraș, Pălatca and Chesău, the pieces grow and thin out.

In the Pălatca forest someone finds an 8.15 kg stone and, out of curiosity, splits it into six with an axe.

### At the far end, the biggest

Near Oláh-Gyéres, today Ghirișu Român, a stone the size of a human head comes down: 8.37 kg.

The largest comes down at the edge of the wood south of Mociu: it strikes a tree, breaks its branches and drives 65 centimetres into the frozen ground. Its heat thaws the snow around it, and the earth turns to mud. The centenary article adds the place: the Paphely wood, about 1.3 kilometres south-east of the village, and the tree was an oak.

### Next day, whole troops go searching

When the people of Coasta learn that the geology professor Antal Koch is buying the stones that fell from the sky, whole troops of men, women and children set out to search the next day. Koch himself found none: his guides spotted them before he did, on the snow.

By the middle of the year 911 pieces had been gathered, weighing 174 kg. Koch reckoned that about 3,000 had fallen, close to 300 kg.

### The villages of the stone field, with their 1882 names

- **Coasta** (Gyulatelke): The densest rain, of small stones. One the size of a fist fell in the main street and was smashed and carried off before the professor arrived.
- **Vișea** (Visa): A stone the size of a pigeon's egg fell among the villagers; another, on a widow's house, was warm when she picked it up.
- **Bărăi** (Báré): A few stones fell between the houses. Koch bought 10 pieces here, of up to 326 grams.
- **Tăușeni** (Marokháza): At the edge of the dense rain, on Koch's map.
- **Vaida-Cămăraș** (Vajda-Kamarás): Four stones given to the museum, almost 1.4 kg together, and a 3.194 kg piece that went to the college in Aiud.
- **Pălatca** (Palatka): In the forest, an 8.15 kg stone, split into six with an axe by the man who found it.
- **Chesău** (Keszü): An intact piece of 4.75 kg and a rough cube of 4.6 kg that went to the British Museum.
- **Ghirișu Român** (Oláh-Gyéres): The second-largest stone, 8.37 kg, the size of a human head, and others of 6.06 and 5.6 kg.
- **Mociu** (Mócs): The 35.70 kg giant, down about 1.3 km south-east of the village, at the edge of the Paphely wood.
- **Bonțida** (Bonczhida): Outside the field. Beside it Koch drew the arrow for the direction the stones came from.

## Why did the big stones fall at the far end?

Set side by side the biggest stone known from each place, north-west to south-east, at scale, and the rule shows itself.

- Coasta, Vișea, Bărăi: 0.845 kg
- Vaida-Cămăraș: 3.194 kg
- Pălatca: 8.15 kg
- Ghirișu Român: 8.37 kg
- Chesău: 4.75 kg
- Mociu: 35.70 kg

Koch explained it like this: the small pieces were the first to lose the speed they brought from space, while the big ones kept it longest, so they fell apart from each other, further and further along the fireball's path. The same rule had been seen in the Pultusk fall of 1868.

By Koch's measure the field is about 15 kilometres long and 3 wide: 45 square kilometres. Only Chesău breaks the line: it lies about as far along the path as Ghirișu Român, but the biggest stone known from there weighs 4.75 kg.

## How heavy was the largest Mociu stone?

35.70 kg. That is what Koch recorded in his February 1882 report for the stone brought to Cluj, which had lost a corner. An American paper of 1961 wrote of “the largest stone weighing about 56 kilograms”. And 56 kilograms is the very figure Koch gave, rounded, for all 102 stones the museum received, weighed together.

### The lots on the scale

- 83 stones from Coasta, Vișea and Bărăi: 8.08 kg. Bought by Koch over two days or given to the museum by the Naláczy family. The biggest of them weighed 460 grams.
- The Mociu giant: 35.70 kg. Brought to Cluj by Koch's colleague Franz Herbich, after a Mociu official, Pál Csobánczi, saved it for science.
- 4 stones from Vaida-Cămăraș: 1.39 kg. Given to the museum by Count Daniel Bethlen.
- 19 pieces brought on 19 February: 1.78 kg. From Chesău, Pălatca, Bărăi and Coasta: 11 whole stones and 8 fragments.
- The second-largest stone: 8.37 kg. The size of a human head, from Ghirișu Român, sent on by Csobánczi too.
- 3 fragments from Gherla: 0.53 kg. Sent by the teacher Ludwig Mártonfi. The largest was said to have been chipped off the giant.

For all six lots together Koch records 102 stones, broken into 121 pieces. The counts in the lot names add up to 111, because the labels mix whole stones, pieces and fragments. Koch does not explain the difference, so the page keeps the total he recorded.

All six come to 55.84 kg, and Koch wrote “rund 56”, about 56. The giant alone is 64% of the weight.

### How big it was

As a sphere of the same rock, the giant would be 27.6 cm across. The 56 kilogram stone of the 1961 paper would have been 32.0 cm. The real one was an irregular pyramid, like the second largest.

## What does a Mociu meteorite look like?

Outside, whole stones wear a thin crust, a third to two thirds of a millimetre thick, dark reddish-brown and usually dull. The small stones found on the snow shone as if varnished. It is the mark of the fall through the air: the stone's surface melted and cooled quickly.

Inside, the rock is light ash-grey, with brown and black veinlets and sparse metal grains that glint. It is crumbly: small pieces can be rubbed between the fingers. In damp air it rusts fast around the iron grains.

Specialists call it an ordinary chondrite, type L5-6, the commonest kind of meteorite.

## Where are the Mociu stones today?

The Natural History Museum in Vienna said in 2012 that it holds the largest collection. A 2010 study counted pieces in more than 30 museums worldwide.

- **Cluj**: In 1979 the university's catalogue listed 63 pieces, the 35.70 kg giant among them. A 2010 study analysed a sample from the Cluj collection.
- **Vienna**: The largest collection, at the Natural History Museum. Tschermak wrote in 1882 that many stones had already arrived there.
- **Budapest, London**: The 8.37 kg stone went to the Hungarian National Museum; a 3.5 kg pyramid and a 4.6 kg cube went to the British Museum.
- **Bucharest, Aiud, Dej**: 3 pieces at Bucharest university, 7 at the Aiud museum and one at the Andrei Mureșanu school in Dej, by a 1968 count.

### The stones weighed by name

- 35.70 kg: Mociu, edge of the Paphely wood → Cluj university (1979 catalogue)
- 8.37 kg: Ghirișu Român → Hungarian National Museum, Budapest
- 8.15 kg: the Pălatca forest → split into six; the merchant Ferenc Benke
- 6.06 kg: Ghirișu Român → the merchant Ferenc Benke
- 5.60 kg: Ghirișu Român → the imperial mineral cabinet, Vienna
- 4.75 kg: Chesău → the pastor Ludwig Mike, Jebucu
- 4.60 kg: Chesău → British Museum, London
- 3.50 kg: between Ghirișu Român and Mociu → British Museum, London
- 3.194 kg: Vaida-Cămăraș → Bethlen College, Aiud
- 3.18 kg: Mociu → Cluj university (1979 catalogue)
- 2.15 kg: Vaida-Cămăraș → the Reformed College, Cluj
- 2.13 kg: the Pălatca–Chesău boundary → the merchant Jakab Azbey, Cluj

The rest scattered into small collections and private hands. Koch wrote as early as February that fine, fairly large stones were still being found, smashed and carried off.

## How we know

The times, places, witnesses and the lots on the scale come from Koch's February 1882 report, read in the German original, and the lot weights were checked on the scanned pages. For the 19 February lots Koch printed a subtotal of 1,598.5 g that leaves out the Chesău fragment; the scale here adds his four rows, 1,775.9 g.

The summer accounts, 911 pieces, 174.115 kg, about 3,000 stones and about 300 kg, come from Koch's second report, known only through quotation in the centenary article of 1980. So do the named stones found after February and the museums they went to.

The dots that light up on the map are the ones Koch printed, read off the scan by their shape; the three hatched squares of the biggest stones were placed by hand. The dots near Bogács are left out: villagers said stones had fallen there, but their direction was about 45° off the fireball's path, and Koch suspected they had been picked up near Coasta and Bărăi. The 5 km scale comes from today's distance between Coasta and Mociu, 14.2 km. The dots light up from north-west to south-east to show Koch's explanation; no source says in what order the stones reached the ground.

Stone sizes are the diameters of spheres at 3.25 g/cm³: Koch's powder weighing (3.609), reduced by a tenth for the rock's pores, following the 5–15% range in the literature.

### Where the sources stop

- No source read gives the fireball's mass, speed or orbit: only its path across the sky, the time and the noise.
- Koch's second report could not be read directly; the summer figures come via quotation.
- Koch writes 45 square kilometres; the 1980 article credits him with 60, perhaps from his second report.
- Only a few stones have their weight by name. Koch's dots are size classes; no catalogue of every stone exists.
- The museum counts come from the 1968–1979 catalogues.

### The fall

- Koch, A. (1882). Meteorsteinfall von Möcs in Siebenbürgen. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, Mathematisch-Naturwissenschaftliche Classe 85, pp. 116–129. https://archive.org/details/sitzungsberichte85kais
- Tschermak, G. (1882). Über die Meteoriten von Mocs. Ibid. 85, pp. 195–209. https://archive.org/details/sitzungsberichte85kais
- Mason, B., Wiik, H.B. (1961). The composition of the Ottawa, Chateau-Renard, Mocs, and New Concord meteorites. American Museum Novitates 2069. https://archive.org/details/compositionotta2069maso
- Brassói Fuchs, H. (1980). Száz éves a mócsi meteorit. Földtani Tudománytörténeti Évkönyv 9, pp. 263–272. https://epa.oszk.hu/03200/03205/00009/pdf/EPA03205_foldt_tudtort_evkonyv_1980-1981_09_263-272.pdf

### The rock

- Tănăselia, C. et al. (2010). Preliminary investigation of Mocs meteorite by lead isotopic ratio. Studia UBB Chemia LV(3). https://repository.ukim.mk/bitstream/20.500.12188/14845/1/XIII_1706.pdf
- Tănăselia, C. et al. (2016). Revised rare earth elements composition of Mocs meteorite. Studia UBB Chemia LXI(3). https://cloud.elearning.ubbcluj.ro/index.php/chemia/article/download/8362/8114/15940
- Korotev, R.L. Meteorite fusion crust. Some Meteorite Information, Washington University in St. Louis. https://sites.wustl.edu/meteoritesite/items/meteorite-fusion-crust-2/
- Flynn, G.J. et al. (2023). Physical properties of the stone meteorites (invited review). NASA NTRS 20230000872. https://ntrs.nasa.gov/api/citations/20230000872/downloads/20230000872.pdf

### The places and museums

- Naturhistorisches Museum Wien (2012). Presseinformation zur Neueröffnung des Meteoritensaals. https://www.nhm.at/jart/prj3/nhm-resp/data/uploads/Presse/Presseinfo_Neueroeffnung_Meteoritensaal_final.pdf
- The fall-field villages' articles on Romanian and Hungarian Wikipedia. https://ro.wikipedia.org/wiki/Mociu,_Cluj