When I designed and knit this hat, we were spending a couple of weeks rock climbing by Scheelite creek. Scheelite is one of the major ores of tungsten and the biggest source of tungsten in the US. Scheelite is quite soft and therefore not normally used in jewelry.
This hat is a little unique in its construction: it is worked sideways, with a cable to connect the hat in the round and finished off with an applied I-cord edge.

Size: sm (med/lg)
To fit up to: 18” (22”/24”); 46cm (56cm/61cm)
Finished Size: 16” (18”/23”); 41cm (46cm/58.5cm)
Height (crown to base of ear): 6.5” (7.75”/8.75”); 16.5cm (20cm/22.5cm)

Materials:
Yarn: 170yds (190yds/220)yds; 156m (174m/202m)/100g worsted weight
Sample shown: Six and Seven Fiber “Wheat”(100% merino) 220yds; (202m)/100g in “The Burrow”