462. Buying Techeiles

Tzitzis 2:6

One may buy techeiles from a seller with an impeccable reputation and it need not be checked. One may rely on such a seller’s reputation until there is a reason to suspect otherwise. If a Jew entrusts techeiles to a non-Jew for safekeeping, it is no longer valid out of concern that he may have exchanged it. If it was in a container that was sealed with two seals, one inside the other, it is valid. If it had only one seal, it is invalid.

Tzitzis 2:7

If one found techeiles in the marketplace, it may not be used, even if they were cut strings (because we don’t know if they were made for the mitzvah). If they were twisted together, they are valid (because one would only go to that much trouble for the mitzvah). If one buys a garment in the marketplace with tzitzis already attached, if he bought it from a Jew, he may assume that it is valid. If he bought it from a non-Jewish merchant, he may likewise assume that it is valid. But if he bought it from a non-Jewish private citizen, it is invalid.