Thank you for submitting your item for appraisal. The Tie tip clip is in white metal and it presents diamonds and emerald. The emerald has a light green, it is rectangular, step cut and it appears to be about 1,30ct approx. It seems natural (probably oiled). The diamonds look H color and VS2, they are round, brilliant cut. The approximate weight is 0.14ct in total. The body part is marked U.S.A. R76759A, another serial number is not perfectly readable. The tie tip seems with the diamonds and emerald seems to be in platinum 900. The small chain could be also in another material since there is no evidence of hallmark. This item is definitely rare and not common in the jewellery market. Observing the photos provided the tie pin clips could be of the '50-'60.
Thank you and feel free to write us if you have any further question.