Does zakat become due on gold that a woman lent to her friend for three years, and is the zakat for one year or more?

As long as the gold has been prepared for wearing, there is no zakat (definition) on it, even if it is lent for a year or more. Lending does not necessitate zakat on jewelry prepared for adornment. This is what Ibn Qudamah stated in "Al-Mughni," quoting it from a number of Companions and فقهاء (jurists), provided that it is prepared for personal use and not for rent, expenditure, or to evade zakat.