Rif Kiddushin 3b {7b}

3b

{Kiddushin 7b}

ההוא גברא דקדיש בשיראי
רבה אמר לא צריכי שומא ורב יוסף אמר צריכי שומא
אי אמר לה בכל דהו כולי עלמא לא [פליגי דלא] צריכי שומא
ואי אמר לה בחמשין ולא שוו חמשין הא לא שוו חמשין
כי פליגי דאמר לה בחמשין ושוו חמשין
רבה אמר לא צריכי שומא דהא שוו חמשין
ורב יוסף אמר צריכי שומא דכיון דאיתתא לא בקיאה בשומא לא סמכה דעתה
והלכתא שיראי לא צריכי שומא

There was a certain man who betrothed with silk. Rabba said this does not require appraisal {to determine its value}. And Rav Yosef said that this requires appraisal.
If he told her it was worth any amount {perhaps a tiny amount; or perhaps as Rashi -- whatever it is worth, for whatever its value, it is not less than a perutah}, the entire world does not [dispute that it does not] require appraisal. And if he told her it was worth fifty and it was not worth fifty, behold it is not worth 50 {and so it is not a valid betrothal}. Where do they argue? Where he told her it was worth 50 and it was indeed worth 50.
Rabba said it does not require appraisal, for behold it is worth 50. And Rav Yosef said that it requires appraisal, for since the woman is not an expert in appraisal, her mind does not rely.
And the halacha is that silk does not require