The dog tag is made of two parts. dog_tag_base.stl weights in silver - 6.14 g, gold 14 K - 7.74 g, gold 18 K - 9.21 g.
ear.stl silver - 0.8 g, gold 14 K - 1.01 g, gold 18 K - 1.20 g.
dog_tag_side.stl It is designed to be made of resin, eg Phrozen Stiff Rock Black. The last photo shows a 3D print of the casting resin for X-One Bluecast.