This is a good question. The Lord of the Flies is a great work with lots of subtle symbols. The conch and Piggy's glasses are very important in the novel.
First, the conch is a symbol of order and civilization. If you recall, there was chaos after the crash. the boys were all over the place and scattered. It was when the conch was blown that the boys came together. More importantly, it created a functional society. To be sure this society did not last all too long as the boys were divided into factions. However, the conch was a civilizing force. The breaking of the conch was also symbolic. The breaking of the conch showed that chaos would now reign.
Second, Piggy's glasses are a symbol of the technology and also to a lesser extent civilization, because the boys were able to make fire through the glasses.