Cotton-synthetic blend

If a sheet is made out of a cotton–blend, when it is part cotton and part synthetic – is it still considered a natural fiber? Must there be a certain ratio of synthetic fiber to natural fiber for it to be considered a synthetic material?
Thank you.

Dear questioner,

Thank you for your question.

There is a difference of opinion regarding the status of synthetic fabrics with respect to tum'ah and taharah (ritual purity).  Presumably, a fabric's status would depend on the majority of its fibers.  But any practical questions should be brought with specifics to a halachic authority. 

If you are purchasing sheets, we suggest purchasing colored sheets for non-niddah times, since stains on colored surfaces are generally treated leniently, regardless of the fabric.  (See our article on stains, "Ketamim", for more details.)

If you have a practical question arising from a stain on a white sheet (as above, stains on colored sheets are generally treated leniently), please contact your local halachic authority or get back to us with details.

This internet service does not preclude, override or replace the psak of any rabbinical authority. It is the responsibility of the questioner to inform us of any previous consultation or ruling. As even slight variation in circumstances may have Halachic consequences, views expressed concerning one case may not be applied to other, seemingly similar cases.

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