It turns out that as with most things, everyone has a favourite style of stitch marker, so here's another option ;-)
I make these simple beaded markers using 0.8mm thick, recycled sterling silver wire, that I solder into rings, having previously threaded one, two or three small sterling beads onto them.
They end up with an internal diameter perfect for any needle up to and including 4mm*
I sell these in sets of 6, a pair each of one, two and three beads to help delineate your pattern. They are surprisingly sturdy, for 0.8mm wire (the same thickness I use to make my ear wires) and are ideal for socks, although they will accommodate needles up to 4mm.
Shown in use with my latest socks (yarn from Bellica Yarns), on a 2.5mm knitPro fixed cable needle, with a pattern tracker, geometric marker and one of my copper cable coils
*I don't recommend having these larger, without also using beads with a larger hole as this size is the sweet spot for the rigidity of the circle.
All my silver is now bought as certified recycled eco-silver, made from 100% scrap / recycled silver which has been fully refined to ensure it is of the same quality as traditional sterling, but of course without the environmental impact of mining it.
Snag Free, closed, beaded sterling silver stitch markers for knitting
Sterling Silver will eventually oxidise or tarnish. It's a natural process that can be slowed down by regular wear and by keeping unworn items away from the atmosphere. If you leave your jewellery out on display, this oxidisation will be faster. You can polish up your items, with a soft cloth, some silver polish, or a buffing cloth such as Town Talk, which is readily available from any high street jewellers in the UK
Fine silver is 99.9% silver, and because of this the tarnish rate is much, much slower. Again, a buff should do the job for polishing it back up. If I have patinated your silver already, be gentle when buffing!
Each piece should stand up to regular wear, but , as with all jewellery, please remove it before washing, using chemicals or applying perfume etc
Apply body lotion and perfume a few minutes before putting on your jewellery to help slow down tarnish
The sterling silver used in these items was sold to me by my bullion dealer as certified recycled.
The gemstones I use have been sold to me by reputable dealers as untreated (unless stated specifically in the listing). They are a natural, organic creation from the earth and each one will be slightly different. You can see examples of this on my Facebook page.
I select the stones that I think go together best for each project, hence my comments that each item is individual.

