Venomweb Glass

Venomweb glass is a toxic resin that is made from the mixing of deadly bloatspider venom and the web of the same creature. These crystalline shapes are found in forests, caves and dungeons where the bloatspiders can be found. The bloatspider vomits its venom onto its prey rather than injecting like other spiders and as a result there can sometimes be a messy residue. The venom itself is a potent toxin that can be collected and stored. It is incredibly sticky, similar to molasses or fresh tree sap. When the venom sets on the web of the spider a chemical reaction occurs making the venom harden like a resin. Once this curing process occurs the material can be ground down and melted into a tertiary material that sets like glass.
The glass can then be poured into a mold of your choosing and the resulting object will continue to inflict the brutal poison damage into whatever creature it wounds.
Most commonly this material is used to make arrow heads, though many members of the Violet Dagger Society have been known to use blades made from the material.