Some of the standard fundamental denominations of gold by weight are grains and pennyweights. "Pennyweight" has an interesting, and significant, back story.
1807 British Half Penny, Reverse
According to Wikipedia:
The pennyweight is the common weight used in the valuation and measurement of precious metals.
Lord Keynes, in attacking the gold standard in his 1930 essay Auri Sacra Fames, commences with the observation that "The choice of gold as a standard of value is chiefly based on tradition. In the days before the evolution of Representative Money, it was natural ... to choose one or more of the metals as the most suitable commodity for holding a store of value or a command of purchasing power."
In deconstructing and ridiculing gold, presenting it as an atavism, Keynes, however, blundered. His claim for the superiority of "Representative Money" -- rather than "Real Money" has been falsified. The fiduciary dollar, a form of Representative Money not convertible to gold at a defined weight, has lost over 80% of its purchasing power in the past 40 some years. The reality of Real Money is reflected in the name and weight of a coin, a Penny weighing a pennyweight, or a Pound Sterling weighing a pound of sterling.
Sometimes tradition contains more wisdom than may be found in well-intended innovation. Keynes, a humanitarian and man of expedients, well might recognize and adapt to this fact were he alive today. As Walter Heller, economist for JFK and LBJ once famously observed, sometimes one must "Rise above principle and do what's right."
History, more than tradition, shows the classical gold standard to be the right thing.