I recently picked these necklaces up at a thrift shop. You may recognise the bottom one- I got another one like it at a junk shop last year and made it into a Venetian necklace-brooch set: http://broidermebethan.blogspot.com.au/2015/02/venetian-necklace-and-brooch-set.html
I planned to do a similar thing, and replace the tiger eye stone with another gemstone. No luck though; I couldn't remove the tiger eye without ruining the setting. Instead I painted the stone with red nail enamel.
The completed set.
The necklace is meant to be worn in this style:
Paolo Caliari Veronese - Portrait of a Woman
Image from: http://starlightmasquerade.com/PortraitGallery/Ladder-Laced-Venetian/inspiration-pages/Venetian2.htm
I am considering adding a drop pearl at the bottom of the brooch where the ends of the necklace join it.
I also picked these earrings up at a thrift shop last year. The black stone matched the necklace, so I painted the diamante with red and black nail enamel to make a dark red accent.