Molten glass got expensive in OSRS because demand surged while supply got tighter, and the most likely trigger in Sept. 2025 was a big crafting-related demand spike rather than a change to the item itself.

What likely drove it

  • Molten glass is a core input for crafting and construction-style progression, so when a lot of players push those skills at once, price jumps fast.
  • Live price trackers show it as an actively traded Grand Exchange item, which makes it sensitive to sudden market pressure.
  • I don’t have a verified patch-note source here that names a single September 2025 update as the cause, so the safest read is that the spike came from market behavior around a content or training rush, not a direct molten glass nerf.

Most common explanations players point to

  1. A new/meta training method made glass-crafting more attractive.
  2. A content update increased demand for crafting supplies.
  3. Speculation and flipping amplified the move once the item started rising.

Practical read

If you saw the price explode in September 2025, that usually means the item became a bottleneck for a high-volume skill route, and merchants/players piled in before supply caught up.

The short version: molten glass became expensive because a lot more people wanted it at once, and the GE is small enough to spike hard when that happens.

TL;DR

  • No clear evidence here of a direct molten-glass-specific nerf.
  • The spike was probably driven by increased crafting demand and market speculation.
  • OSRS supply items can jump sharply when a training method becomes popular.