Leather jackets and wooden chairs: saying what things are made of with 'en'
In English, you name the material first and then the object: a leather jacket, a wooden chair, a glass bottle. French does it the other way round. The object comes first, then the little word en, then the material, with no article at all: une veste en cuir, une chaise en bois, une bouteille en verre. The same pattern works for clothes and fabrics like laine, soie and coton, for metals like or and argent, and for everyday materials like plastique and papier.
English speakers tend to trip up in three ways. They keep the English word order (un cuir veste does not exist). They slip in an article (en le bois, en du coton). Or they look for an adjective, because English has wooden and woollen. In French, you almost never need one: en plus just the noun does the job.
Word list
chocolatmA1chocolateun lapin en chocolat = a chocolate bunnypapiermA1paperun avion en papier = a paper aeroplanesucremA1sugardes fleurs en sucre = sugar flowersargentmA2silverune bague en argent = a silver ringboismA2woodune chaise en bois = a wooden chairbronzemA2bronzeune statue en bronze = a bronze statuecuirmA2leatherdes chaussures en cuir = leather shoesfermA2ironun portail en fer = an iron gatemétalmA2metalune chaise en métal = a metal chairormA2goldune montre en or = a gold watchpierrefA2stoneune maison en pierre = a stone houseplastiquemA2plasticun sac en plastique = a plastic bagverremA2glassune bouteille en verre = a glass bottlebriquefB1brickune maison en brique(s) = a brick houseen orB1goldenune montre en or = a gold watchfil de fermB1wireune sculpture en fil de fer = a wire sculpturefil métalliquemB1wireun panier en fil métallique = a wire basketlainefB1woolun pull en laine = a wool jumperosmB1boneun couteau à manche en os = a bone-handled knifepinmB1pine treeune étagère en pin = a pine shelfsac en plastiquemB1plastic bagun sac en plastique = a plastic bagsoiefB1silkune écharpe en soie = a silk scarfaciermB2steelune poutre en acier = a steel beamaluminiummB2aluminiumune canette en aluminium = an aluminium canavion en papiermB2paper airplaneun avion en papier = a paper aeroplanebamboumB2bambooune brosse en bambou = a bamboo brushbétonmB2concreteun mur en béton = a concrete wallcaoutchoucmB2rubberdes bottes en caoutchouc = rubber bootscarbonemB2carbonun vélo en carbone = a carbon bikecartonmB2cardboardune boîte en carton = a cardboard boxcéramiquefB2ceramicun vase en céramique = a ceramic vasechênemB2oakune table en chêne = an oak tablecirefB2waxune statue en cire = a wax figurecornefB2hornun peigne en corne = a horn combcotonmB2cottonune chemise en coton = a cotton shirtcristalmB2crystalun verre en cristal = a crystal glasscuivremB2copperune casserole en cuivre = a copper panfourrurefB2furun manteau en fourrure = a fur coatgranitmB2graniteun plan de travail en granit = a granite worktopmarbremB2marbleun escalier en marbre = a marble staircasemassepainmB2marzipandes fruits en massepain = marzipan fruitsmoussefB2foamun matelas en mousse = a foam mattressplombmB2leaddes soldats en plomb = lead soldiersporcelainefB2porcelainune tasse en porcelaine = a porcelain cuptissumB2tissueun sac en tissu = a cloth bagtissumB2textileun sac en tissu = a textile bagacier inoxydablemC1stainless steelun évier en acier inoxydable = a stainless steel sinkambremC1amberun collier en ambre = an amber necklaceargilefC1clayun pot en argile = a clay potinoxmC1stainless steelune casserole en inox = a stainless steel panivoiremC1ivoryune statuette en ivoire = an ivory figurineliègemC1corkun bouchon en liège = a cork stopperlinmC1linenun pantalon en lin = linen trouserspaillefC1strawun panier en paille = a straw basketplatinemC1platinumune bague en platine = a platinum ringtissumC1fabricdes chaussures en tissu = canvas shoeszincmC1zincun toit en zinc = a zinc roofalliagemC2alloydes jantes en alliage = alloy wheelscire d'abeillefC2beeswaxune bougie en cire d'abeille = a beeswax candlecontreplaquémC2plywoodune étagère en contreplaqué = a plywood shelfcorailmC2coralun collier en corail = a coral necklaceétainmC2tinune assiette en étain = a pewter plateferraillefC2scrap metalune sculpture en ferraille = a scrap-metal sculpturelaitonmC2brassune poignée en laiton = a brass handleosiermC2wickerun panier en osier = a wicker basketpain d'épicesmC2gingerbreadune maison en pain d'épices = a gingerbread houseplâtremC2plasterun moulage en plâtre = a plaster castrésinefC2resinune chaise de jardin en résine = a resin garden chairtitanemC2titaniumdes lunettes en titane = titanium glassesveloursmC2velvetune veste en velours = a velvet jacket
How it works
The pattern is always the same: object + en + material. The noun for the material is used on its own. There is no article, it does not become plural, and it does not agree with anything. One silk scarf and ten silk scarves are both en soie.
Il porte une veste en cuir.
(He's wearing a leather jacket.)
You can also use en after être to say what something is made of. This is the French equivalent of English made of. To ask the question, say C'est en quoi ? (What's it made of?).
Ces écharpes sont en soie.
(These scarves are made of silk.)
Rule of thumb: if you can say made of X in English, you can almost always say en X in French.
The words
Clothes and fabrics
For what you wear, the usual materials are cuir, laine, soie, coton, lin, velours and fourrure. The general word for fabric is tissu: un sac en tissu is a cloth bag.
J'ai acheté un pull en laine pour l'hiver.
(I bought a wool jumper for the winter.)
Elle porte une chemise en coton et un pantalon en lin.
(She's wearing a cotton shirt and linen trousers.)
Metals
Jewellery, tools and statues follow the same pattern: or, argent, platine, bronze, cuivre, laiton, fer, acier, acier inoxydable (in everyday speech inox), aluminium, zinc, étain, plomb, titane, and the general word métal.
Ma grand-mère m'a donné une montre en or.
(My grandmother gave me a gold watch.)
C'est une statue en bronze.
(It's a bronze statue.)
Everyday materials
Around the house and in buildings you will meet bois, plastique, verre, papier, carton, pierre, marbre, granit, béton, plâtre, contreplaqué, céramique, porcelaine, cristal, argile, caoutchouc, liège, bambou, osier, paille, cire and ivoire.
La table est en bois, mais les chaises sont en métal.
(The table is wooden, but the chairs are metal.)
Tu préfères une bouteille en verre ou en plastique ?
(Do you prefer a glass bottle or a plastic one?)
Mets les livres dans une boîte en carton.
(Put the books in a cardboard box.)
Some combinations are so common that they are learnt as whole phrases, such as sac en plastique and avion en papier.
Les enfants ont fait un avion en papier.
(The children made a paper aeroplane.)
Watch out
Sometimes it's de
You will also hear de instead of en, especially in fixed or slightly old-fashioned expressions: un manteau de fourrure, un chapeau de paille, un pull de laine, une bague d'or. Both are correct, but en is the safe everyday choice. Use de mainly for the fixed phrases you have actually heard.
Il fait chaud, prends ton chapeau de paille.
(It's hot, take your straw hat.)
Dropping the preposition
In casual speech, a few very common items lose en altogether: un sac plastique is as common as un sac en plastique. Don't generalise this to other materials.
Material or colour?
En or means made of gold. For something gold-coloured, French uses the adjective doré. En or also has a figurative sense: une occasion en or is a golden opportunity.
The typical mistake
Never add an article after en. Say une chaise en bois, not une chaise en le bois or en du bois.
Summary
To say what something is made of, put the object first, then en, then the material noun with no article: une veste en cuir, une montre en or, une boîte en carton. Use the same pattern after être (c'est en bois). A few fixed phrases prefer de, like un chapeau de paille, but when in doubt, en is the natural choice.