For a 12”/30cm cushion on US size 2 (2.75m needles)
Fingering weight yarn in the following quantities:
Dark blue/green fingering weight yarn (Suggested:Jamieson & Smith 2ply Jumper Weight (4ply weight / fingering; 100% real Shetland wool; 115m/125 yards per 25g ball), colourway fc41, Dark Teal Blue). Approx 75 yards (70m).
Dark teal fingering weight yarn (Suggested:: Jamieson & Smith 2ply Jumper Weight (4ply weight / fingering; 100% real Shetland wool; 115m/125 yards per 25g ball), colourway fc34). Approx 150 yards (140m).
Mid teal fingering weight yarn (Suggested: Jamieson & Smith 2ply Jumper Weight (4ply weight / fingering; 100% real Shetland wool; 115m/125 yards per 25g ball), colourway 071, Bright Turquoise). Approx 265 yards (250m).
Pale teal fingering weight yarn (Suggested: Jamieson & Smith 2ply Jumper Weight (4ply weight / fingering; 100% real Shetland wool; 115m/125 yards per 25g ball), colourway 075, Light Turquoise. Approx 450 yards (420m).

OR

For 16”/40cm cushion on US size 4 (3.5mm) needles
DK weight yarn in the following quantities:
Dark blue/green DK weight yarn Approx 100 yards (95m).
Dark teal DK weight yarn Approx 200 yards (185m).
Mid teal DK weight yarn. Approx 350 yards (320m).
Pale teal DK weight yarn. Approx 600 yards (550m).