Contemporary Studio Modern Artisan Amethyst Boulder Sterling Silver Necklace

I have looked high and low to identify the maker of this piece - with no luck - signed: '925 M Di' Unique and amazing - HUGE rough faceted amethyst gemstone beads with one faceted brushed silver spacer in the shape of a diamond - strung on 1mm sterling cable with interlocking C form links as a clasp - 13 gemstones in all measuring approximately 30x30mm each - is that 150 carats each? very hard to calculate - please measure carefully - there is no adjustment for this statement necklace - 18" long and weighs approximately 1 pound - 16 oz on my postal scale - some tarnish as I found it - otherwise excellent.

*I will do my absolute best to describe each item as accurately as possible and to the best of my knowledge. That being said, please note that my items are vintage, often unique and unless otherwise noted not in mint or new condition, light wear consistent with age and use must be expected. Please read the description carefully, do your own due diligence and don't hesitate to email with any questions. I want you to be happy with your purchase and will do everything possible to make this a positive experience.