Below is a list of the popular units of measure when referring to gold weight:

Grains (gr):  This name originated from the weight of a dried seed of corn or as some believe a grain of wheat.

  1 grain   = 64.8 milligrams
24 grains = 1 Pennyweight

Gram (g):

1 gram = 15.432098 grains

Pennyweight (dwt): This name originated from the weight of an Anglo Norman silver penny in medieval England.

1 pennyweight = 24 grains
                       = 1.5552 grams

Ounce (oz) Av.:

1 ounce (Av) = 437.5 grains
                      = 28.35 grams
                      = 18.2291 pennyweight

Ounce (oz) Troy:

1 ounce (Troy) = 480 grains
                        = 31.104 grams
                        = 20 pennyweight

Pounds Av.:

1 pound (Av) = 7000 grains
                      = 453.6 grams
                      = 291  2/3 pennyweight
                      = 16 ounces (Av)

Pounds Troy:

1 pound (Troy) = 5760 grains
                         = 373.248 grams
                         = 240 pennyweight
                         =12 ounces (Troy)