... bought by a space traveler visiting an unfamiliar planet. The scarf pulls him into another dimension/realm/universe. Very spooky tone. Read it decades ago in an anthology.
Any clues? Thanks.
If the "scarf" is a shawl (actually the protagonist does call it a scarf when he first sees it) and the "unfamiliar planet" is Mars, you could be talking about "Scarlet Dream", a novelette by C. L. Moore in her Northwest Smith series, also the (unaccepted) answer to the old question Cannot find this short story: man buys rug, falls asleep, finds himself in deadly world. Originally published in Weird Tales, May 1934 (available at the Internet Archive), it was reprinted in Avon Fantasy Reader No. 5, 1947 (also available at the Internet Archive) and in various anthologies and collections. Any of these covers look familiar?
Looking for short story about a scarf bought by a space traveler visiting an unfamiliar planet.
Northwest Smith bought the shawl in the Lakkmanda Markets of Mars. It was one of his chiefest joys to wander through the stalls and stands of that greatest of market-places whose wares are drawn from all the planets of the solar system, and beyond. So many songs have been sung and so many tales written of that fascinating chaos called the Lakkmanda Markets that there is little need to detail it here.
[. . . .]
"How much for the scarf?"
The man—he was a canal Martian—glanced over his shoulder and said carelessly, "Oh, that. You can have it for half a cris—gives me a headache to look at the thing."
Smith grinned and said, "I'll give you five dollars."
"Six and a half, and that's my last offer."
"Oh, take the thing." The Martian smiled and lifted the tray of ivory beasts from the chest.
Smith drew out the shawl. It clung to his hands like a live thing, softer and lighter than Martian "lamb's-wool." He felt sure it was woven from the hair of some beast rather than from vegetable fiber, for the electric clinging of it sparkled with life. And the crazy pattern dazzled him with its utter strangeness. Unlike any pattern he had seen in all the years of his far wanderings, the wild, leaping scarlet threaded its nameless design in one continuous, tangled line through the twilight blue of the background. That dim blue was clouded exquisitely with violet and green—sleepy evening colors against which the staring scarlet flamed like something more sinister and alive than color. He felt that he could almost put his hand between the color and the cloth, so vividly did it start up from its background.
"Where in the universe did this come from?" he demanded of the attendant.
The man shrugged.
"Who knows? It came in with a bale of scrap cloth from New York. I was a little curious about it myself, and called the market-master there to trace it. He says it was sold for scrap by a down-and-out Venusian who claimed he'd found it in a derelict ship floating around one of the asteroids. He didn't know what nationality the ship had been—a very early model, he said, probably one of the first space-ships, made before the identification symbols were adopted. I've wondered why he sold the thing for scrap. He could have got double the price, anyhow, if he'd made any effort."
The scarf pulls him into another dimension/realm/universe.
When he slept that night he spread the bright shawl across his bed, and the brilliance of it colored his dreams fantastically. . . .
[. . . .]
"Oh . . . you come from—from—you still believe that you dream!"
"I know I'm dreaming," persisted Smith childishly. "I'm lying asleep in Lakkdarol and dreaming of you, and all this, and when I wake—"
She shook her head sadly.
"You will never wake. You have come into a more deadly dream than you could ever guess. There is no waking from this land."
"What do you mean? Why not?" A little absurd panic was starting up in his mind at the sorrow and the pity in her voice, the sureness of her words. Yet this was one of those rare dreams wherein he knew quite definitely that he dreamed. He could not be mistaken. . . .
"There are many dream countries," she said, "many nebulous, unreal half-lands where the souls of sleepers wander, places that have an actual, tenuous existence, if one knows the way. . . . But here—it has happened before, you see—one may not blunder without passing a door that opens one way only. And he who has the key to open it may come through, but he can never find the way into his own waking land again. Tell me—what key opened the door to you?
"The shawl," Smith murmured. "The shawl . . . of course. That damnable red pattern, dizzy—"
He passed a hand across his eyes, for the memory of it, writhing alive, searingly scarlet, burned behind his eyelids.
Read it decades ago in an anthology.
If it was a multi-author anthology rather than a Moore collection, and if "decades ago" was before 1993, then it was probably the 1952 hardcover anthology Future Tense edited by Kendall Foster Crossen.