Can you just pick up nuggets of cobalt and gold?
By defination everything on the moon is rare, as the word is used on the earth anyway.
No.
The moon consists mostly of feldspar and pyroxene which are, unremarkably, the first and second most common minerals on Earth. The moon does consist of a lot of the rock Anorthosite in addition to the basalts[li], which is fairly uncommon on Earth, but the minerals which make up Anorthosite aren’t anything you wouldn’t find on Earth.[/li]
[li]Lunar basalt is higher in K, REE, and P than terrestrial basalts (and are termed “KREEP Basalts”), which makes them unusual and results in higher concentrations of REE in the plagioclase. They are also a bit higher in Ti, which might give them more ilmenite than your terrestrial basalt.[/li]
And there are certainly no nuggets of cobalt or gold.
http://www.minsocam.org/MSA/AmMin/TOC/Abstracts/2003_Abstracts/FM03_Abstracts/Papike_p469_03.pdf
http://solarsystem.estec.esa.nl/Moon2000/abs45_pieters.PDF
Once I got my lazy ass of the internet and looked through an actual book (Handbook of Mineralogy–Volume II: Silicates, which is ironically also available on-line at http://www.minsocam.org/MSA/Handbook/), I found the following minerals that–while not abundant–have only been described from lunar samples:
Tranquillityite Fe[sub]8/sub[sub]2[/sub]Ti[sub]3[/sub]Si[sub]3[/sub]O[sub]24[/sub]
and
Pyroxferroite (Fe, Mn, Ca)SiO[sub]3[/sub]
Rare Earth Elements -> REE