Full Idea
If malleableness makes not a part of the specific essence the name 'gold' stands for, 'tis plain, 'all gold is malleable' is not a certain proposition.
Gist of Idea
For 'all gold is malleable' to be necessary, it must be part of gold's nominal essence
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 4.06.08)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.583
A Reaction
So why would we think that being malleable was part of the essence of gold, while being shaped like a wedding ring was not? The answer is that we are not only concerned with the 'nominal' essence.