Reading the server's economy without reading it as a shop price list
Zen in circulation is the total Zen currently held across every account — a snapshot of the server's money supply, not a price. Items in-game counts everything that currently exists in the world: equipped, in an inventory or sitting in a warehouse. Rare items narrows that same count to Excellent-tier and other rare pieces, so it moves independently of the total.
Bless, Soul, Chaos, Life, Creation, Harmony and Guardian jewels are all player-traded, so there is no fixed shop price for any of them — the average shown above reflects what players are actually paying on the market. The chart tracks how that average has moved over the last 30 days, which is a better read on supply and demand than any single sale.
This page is a summary of the economy, not the trading interface itself — to see live listings and actually buy or sell, use the Player Market.