HaShem first told us of His command to Moshe to tell the People of Israel to donate gold and silver (and other materials) back in Parshat T'ruma. Before Moshe had a chance to transmit that command to the People, the Eigel HaZahav happened.
Donation of gold, let's call it, for the WRONG PURPOSE. Then in Parshat Vayakhel, the request went out for the materials to be donated, for the RIGHT PURPOSE. And in this week's sedra, we have the amounts that were donated of each of the metals.
The major difference between gold and silver (besides all their obvious differences) is that no amount or limit was specified for the gold, and a very specific and fixed amount was commanded for that generation and for all times, for silver. This, by itself, is an important lesson.
Sometimes, giving more is helpful and a praiseworthy thing. But sometimes it is not. Sometimes it is very important for all members of a community to share equally in providing for the needs of the community. Specifically, the equally shared "burden" of the required silver for the Mishkan was used for the foundation of the structure.
The silver ADANIM were donated by everyone equally. Good lesson in that. The Machatzit HaShekel tax for future generations was equally significant in the fact that the basic Mikdash needs of the community were shared equally by all. Gold, on the other hand, needed to be given on a freer basis, perhaps because the donations to the Eigel project were also contributed with an enthusiasm that needed serious repair – TIKUN.
If this has been the basic gold and silver lesson, then let's extend it in a different direction, based on the continuation of Parshat P'kudei. Different writers in this issue of TT have made reference to the phrase repeated over and over again, that Bnei Yisrael did exactly as G-d had commanded Moshe. Aharon HaKohen is complimented in commentary on the beginning of B'haalot'cha for doing exactly what he was commanded. Sometimes, that is what we all must do – what we are commanded to do.
On the other hand, we have KOL HAMARBEH… HAREI ZEH M'SHUBACH, the more one does… the more praiseworthy it is. HAMACHMIR TAVO ALAV B'RACHA, one who is strict (and goes beyond the requirement of halacha), a blessing on his head (as Tevya would say). One gets the feeling sometimes, that if there would not be super-strict performance of certain mitzvot by certain segments of Klal Yisrael, maybe more non-observant Jews would keep more mitzvot. (Controversial statement that needs further clarification; hopefully, the idea will be understood by you) We need the wisdom to know when to give gold to our heart's content and when to give silver-style.