High grade spider webs

The richest people in the world build monuments from this stuff. Where do you get it and what special properties does it have?
The largest air to ground structures on Boscage 4 are reinforced with spider silk from the Drow Kingdom of Zarlan, which is not cheap. High grade spider webs help protect against earth quakes and the effects of gravity at high altitudes, allowing the beams to bend in the wind and not break. Some airships are reinforced with this material as well, but a thinner strand is needed for fine work and is more costly than the average stock.
Architecture projects reinforced with spider silk cost x4 the base cost, but is immune to normal earth quakes, and allows buildings up to 24 stories tall VS 8 stories from traditional red mud brick. Architecture grade spider web strands are sticky thick cables which have resistance to fire naturally.
Airships and other larger vehicles reinforced with fine spider silk cost x6/x8 the base cost, but the ship's AC is raised by +4, it's hit points are doubled, and it has advantage when it crashes or gets rammed. Normal bludgeoning, piercing, and slashing weapons do half damage, but magical weapons work fine. Fire does normal damage if the flame retardant chemical was applied for the x8 the cost, or is vulnerable to fire and takes double damage if the user paid the x6 cost. Don't skimp on the upgrades.
Stringed weapons like bows and cross bows may use fine spider silk as well, but each strand costs x12 the base cost of the stringed weapon and lasts a long time, but is vulnerable to fire. The effects are +1 damage and increased rage by +20/+20. For x8 the base cost of the stringed weapon the user may get rid of the vulnerability to fire. Miss Willa Zill'xar Web Weaver, singer of epic ballads and poems, uses this quality of spider silk for her instruments.
Spider silk armor is like master grade cloth armor, but it fits under normal armor and clothing just fine, and doesn't give disadvantage on stealth checks. For x6 the base cost of a piece of armor or shield, one may have it manufactured from spider silk to give it 80% less weight, receives resistance VS bludgeoning, piercing, and slashing weapons, but receives vulnerability to fire taking x2 damage. If you know the enemy doesn't use fire, then spider silk armor and shield are amazing, but if they do, for x12 the base cost of a piece of armor or shield the user may get rid of the vulnerability to fire.

Type

Organic