Shemos 32:2-3 tells us that the gold materials requested and used for the making of the golden calf were earrings. The Jews clearly had other gold items, including other golden jewlery (ibid 35:22). Is there any symbolism behind why earrings specifically were chosen?
BS"D, Hakham Eli Mansour makes this connection 'al pi HaRav Shimon Schwab in his shi'ur on Parashat Ki Tisa 5774 (link, see 17:15-28:00).
HaRav Mansour explains HaRav Schwab by starting with the fact that it was the men who gave the gold from their earrings to Aharon after their wives refused to hand over their jewelry for the purposes of 'Avodah Zarah (for which, he explains, Rosh Hodesh was dedicated to Jewish women). His support for this conclusion is the word "Ozneihem" in Shemot 32:3. HaRav Mansour goes on to ask why men were wearing earrings in the first place.
He explains that, after miraculously hearing HaShem's voice with their own physical ears, the Jewish men wanted to adorn their ears with gold to underscore and remember the miracle (as, he explains, we do with hidurim of many of the mitzwot).
Tangentially, he explains that earrings are a remembrance that we are slaves only to HaShem and that that is why a Jewish slave has his ear pierced on a doorpost for choosing to extend his slavery to another human being. Here, at Mt. Sinai, the Jewish men pierced their ears to honor and remember "Anokhi HaShem Eloqeikha".
He concludes this section of his shi'ur by tying these teachings together to explain why Het Ha'Egel was such a grave sin. The men rushed to use the gold from the earrings they had, only days before, sanctified for the remembrance of hearing HaShem speak and command them to serve Him alone all in order to worship an idol. For this grave sin, they and their descendants came to deserve a severe punishment indeed.
All of the commentators understand that during these proceedings, Aharon tried to delay the process as much as possible, hoping that Moshe would eventually come and even negate it completely or that there will be refusal by others to give from their own belongings, etc. He tactfully used specific words to prolong the matter. In this vein, I would venture to say that earrings were the most commonly used adornment and would take the longest time to gather (this is perhaps alluded to in the Or Hachaim quoted below). Even the men wore earrings then (and in fact that alone was what was used to make the golden calf). See Pirkei Dirabbi Eliezer 45 and Tanchuma 21.
The reason why not request everything, the Or Hachaim (Exodus 32:2) explains: "[The verse says:] "Break off" - you and not they. "Golden earrings" - not other gold. "Which are in the ears of" - and not laying in a chest, and they should not put them on after [and subsequently break them off]. If this is not carried out, this hinders [the fulfillment of the instruction]." Aaron was pretending he needed 'this and not that'. On the flipside though, he requested the most time-consuming activity; gathering the golden earrings.
Symbolically speaking, Rabbi Yitzhak Ginsburg Shlita, Rosh Yeshiva of 'Od Yosef Chai', observes that letters of "נזם", the word used here for 'ring', can be rearranged into "זמן". There are two types of negative elements related to זמן, time; עזות דליפה and בושה דקליפה. In its very basic form it's the idea of always being early or always being late, but in a deeper sense it refers to other things, like being too aloof or being too involved in something. The sin of the golden calf was a misguided reaction to an observation the Children of Israel made about Moshe. He seemed to be too spiritually aloof, and indeed they were correct, for Moshe did not sense enough the sin they subsequently partook in and intervene (though upon realization he rectified it by destroying the tablets). This came from בושה דקליפה. As the first verse in the chapter states: וירא העם כי בשש משה לרדת מן ההר. Which literally means he delayed. But is also etymologically connected with this notion of בושה דקליפה. See here for his exhaustive treatment of the matter.