Okay, so S and Damien were tasked with learning how to transmute several materials for their supplementary exercises, and these includes both diamond and spider silk.
One of those materials is very hard, but also brittle.
The other is soft and flexible, but has high tensile strength.
Those are two types of materials that compliment each other remarkably well when used together.
Siobhan imagines diamond-based knives and armor, but decides that they aren’t viable because of how brittle they are. But if she, for example, made armor composed of alternating thin sheets of the two materials she could get some incredibly strong (albeit impermanent) armor.
The silk as a backing material would give it some shatter-resistance and distribute force laterally, while the diamond would let it resist cutting, add rigidity that would help against blunt impacts, and would serve to absorb some of the force of blows when they break the diamond bonds, similar to modern ballistic armor. It would become much less useful after a few strikes, but those few strikes would all be lifesaving.
Could growing diamond around a framework of wires operate similarly to steel-reinforced concrete, just on a smaller scale?
Are there other ways you can see for her to combine the materials that she is working to be able to synthesize freely?