1. If I do not usually say shehechiyanu upon buying new clothing (even Shabbos clothing), can I but and wear them during the 3 weeks?
2. Can I buy and wear new necklace during the 3 wks? Does it make a difference if I am wearing it on Shabbos? Does it make a difference if it is not “real” silver/gems?
1. For important new clothing the Shehecheyanu berachah should be recited. For this reason we try to avoid the purchase of new clothing (important) in the Three Weeks. However, it is not forbidden to buy new clothing, and one who does so should preferably wear the item of clothing on Shabbos for the first time, and recite the berachah on Shabbos, for which many authorities, including the Mishnah Berurah, are lenient.
2. The same principle applies. If it is an important/expensive item of jewelry and bring you joy, Shehecheyanu should be recited. In this case, it should be worn first on Shabbos.