These are not coins, but rather Tempe Tokens, or Ramatanka. The inscriptional side has the Kalimah in the center, with legends around reading Abu Bakar the Just / Umar the Preacher / Uthman the High / Ali Haydar. Actual Rupee coins with a similar pattern were issued by Mughal Emperor Akbar I, 1542-1605. The other side is a Mosque with inscription Medina the Noble below. I don't know if it is a particular building, or a generic Mosque. There have been many versions made of this temple token design, the better silver ones possibly dating to the 1700s, down to brass ones made in recent decades. Yours appear to be middling fineness silver, so guessing broadly 1800s. I have handled hundreds of temple tokens in various designs over the years and rarely found them with mounting damage, but I suspect this means that damaged pieces rarely enter the coin trade, rather than suggesting that they were seldom used in jewelry.

Shown are two large, early fine-style examples, a piece similar to those in the necklace,and a variant design that has been mounted.