Red Acrylic Heart Beads, sized 8mm x 7mm with a hole top to bottom.
Sold in a bag of 30 hearts. Laying flat in your work the hole can't be seen.
You can use these in indoor mosaics. As they are acrylic you could probably scratch them up a bit if you are a rough grouter. There is a ridge between the white and the colour, so grout would probably want to accumulate in there. Alternatively you can use them embedded in adhesive in non-grouted work. You can cover the top with tape or plasticene. Or you can glue these on top of your work for an added dimension. Also great for micro work.
"Don't be limited by your materials, play with your tesserae." Karen Baker.