Ad Astra Unlimited Resource Encyclopedia: A Shard Of Knowledge
Shards is a blanket term, and can come in many forms but are generally a piece of information, or important component that allows settlers to further increase the effectiveness of their buildings. Due to lost knowledge and patenting, the information isn't publicly available, leading to settlers having to exchange shards in trading bazaars or dismantle their own Duskwork's buildings in order to create their own more efficient designs. Shards can also be purchased off of the marketplace, in exchange for Dusk.
Some other types of shards, include the original blueprint plans for extremely well built "artifact" buildings that have been lost, using these original pieces of the blueprint they can rebuild the artifact.
For the trading bazaars, cantinas and other special buildings, they're simpler to upgrade, requiring only one type of information shard that will allow you to further the reach of these buildings through better communication equipment and other logistical systems.
Shards come in three types: