Profane Wand

The Iron Capped Profane Wand is a Thaumcraft wand which uses the profane rod (added by Forbidden Magic) as its core. It has the ability of instantaneously recharging its vis, at the cost of adding normal (sticky) warp to the player holding it. This wand is notorious in GTNH because it is obtainable from villagers and has a capacity of 50 vis (comparable to greatwood wands).

Obtaining
The profane wand can only be obtained by trading with Heretic Villagers. They may trade a stick and between 8 and 12 emeralds for a wand.

These villagers spawn naturally in villages, and can be randomly bred from adult villagers, making the wand available straight from the start. This technically allows players to get started with Thaumcraft in the stone age.

Usage
The profane wand behaves similarly to other wands in respect to its usage in e.g. the Arcane Worktable. The only differences are that the wand starts precharged with 50 vis of each primal aspect, and it has a "contract" recharging mechanic. Note that it has 110% vis cost, so crafting with this wand is a bit more expensive than usual.

The wand starts with 25000 contract, representing the fact that it can replenishes up to 250 vis (25000 hundredths of vis). The remaining contract is visible in the tooltip. If the wand is not full, it will recharge its vis and deplete its contract, at the rate of 1 point of vis for each 100 points of contract. Every time this happens, the player has a chance of getting one point of warp, proportional to the amount of vis replenished.

In detail: the wand attempts to recharge the aspects in order (aer, terra, ignis, aqua, ordo, perditio). For each attempt, it will either fully recharge that aspect, or spend as much contract it has available, at a rate of 100 contract points for each vis point. It then has a chance of giving the player one point of normal (sticky) warp; the probability is $$\frac{\mathrm{spent\ contract}}{2501}$$, capped at 100%.

For example, crafting a cloak requires 10 aer; with the 110% vis cost, this drains 11 aer from the wand. When holding the wand, this costs 1100 contract points to replenish, so this craft has a $$1100/2501 \approx 44\%$$ of chance of giving the player a point of warp. If four cloaks are crafted in a row, without moving the wand to the player's inventory, then the contract cost of 4400 exceeds 2501, so this guarantees a single warp point. Finally, crafting a sliver of air costs 10 perditio and 5 aer, draining 11 perditio and 5.5 aer from the wand; when replenishing, the wand first drains 550 contract points to replenish aer, giving one warp with probability $$550/2501 \approx 22\%$$, and then drains 1100 contract points to replenish perditio, giving one warp with probability $$1100/2501 \approx 44\%$$. Thus the player may gain between 0 and 2 warp in this process.

Once the contract reaches zero, the player receives one additional warp point, and the wand becomes a normal wand thereafter.

Managing/cheesing the profane wand
If all replenishing attempts cost less than 2501 contract points (25.01 vis, or 22.7 vis before the 110% cost modifier), the player will get, on average, $$25000/2501 \approx 10$$ warp (plus the end-of-contract warp). In isolation this much warp should be no cause for concern, but could get annoying when combined with other sources of warp.

We can reduce the warp given by the profane wand by exploiting two properties of the contract mechanic: first, that whenever we spend more than 2501 contract points at once, the additional points do not give extra warp; and second, that the mechanic only takes place if the wand is in a player's inventory.

By leaving the wand in the arcane worktable, we can craft multiple items without triggering the contract mechanic. This makes it easier to surpass the 25 vis needed before extra spent vis do not translate into extra warp. You can use another wand in the meanwhile to interact with the world (e.g. dumping water from a crucible); unless these interactions drain vis, this will not give you warp. Theoretically, fully draining the wand depletes all contract points and gives exactly 5 warp, plus the single end-of-contract warp.

Finally, if the wand is not touched again (for example, by leaving it in the arcane worktable, or by dropping it in lava without touching the player's inventory), the player will not receive warp, and another fully charged wand can simply be purchased for a stick and a few emeralds.