**Core Concept**
Chalcosis is a condition characterized by the deposition of copper in the eyes, particularly in the cornea and iris, due to the presence of a foreign body, usually an intraocular copper foreign body. This condition leads to various ocular manifestations, including corneal opacification, iris heterochromia, and glaucoma.

**Why the Correct Answer is Right**
The deposition of copper in the eye occurs due to the breakdown of the copper foreign body, releasing copper ions that are then deposited in the surrounding ocular tissues. This process is facilitated by the presence of copper ions in the aqueous humor, which can lead to the formation of a copper-protein complex. The subsequent deposition of copper in the cornea and iris can cause corneal opacification, iris heterochromia, and glaucoma.

**Why Each Wrong Option is Incorrect**
* **Option A:** Chalcosis is not typically associated with the deposition of iron in the eye, which is more characteristic of siderosis.
* **Option B:** While chalcosis can cause corneal opacification, it is not a result of the deposition of calcium in the cornea.
* **Option C:** Chalcosis is not a condition caused by the deposition of zinc in the eye, which is more characteristic of a different ocular condition.

**Clinical Pearl / High-Yield Fact**
Chalcosis is a rare but serious condition that can result from a penetrating eye injury with a copper foreign body. Prompt removal of the foreign body and treatment with copper-chelating agents can help prevent long-term ocular damage.

**Correct Answer: D.**