Shards Like Glowing Embers

Scattered almost haphazardly throughout this digsite, the crew and I have found these strange reddish-orange crystal shards. Approximately the size of my palm, give or take, they are light but incredibly strong. It is unclear what they may have been used for, but given the tool marks on the edges, these may have been common to the Ancients. They could have even been decoration on something that has long since been lost to time, or common tools, or have any number of other uses.