What type of kidney stone is characterized as radiopaque and envelope-shaped?

Calcium oxalate stones are indeed characterized as radiopaque and have an envelope-like shape, which is a distinctive feature often seen on imaging studies. These stones form when calcium combines with oxalate, a compound found in many foods, including leafy greens and chocolate, among others.

The radiopacity of calcium oxalate stones is due to their calcium content, which makes them visible on X-rays because they can block the passage of X-ray beams. This visibility aids in diagnosing kidney stones since a patient may present with flank pain or hematuria, and imaging can confirm the presence of these stones.

The envelope shape of calcium oxalate stones is specifically linked to the dihydrate form (calcium oxalate dihydrate), which is the most common form associated with kidney stone disease. This shape is crucial for distinguishing them from other types of stones, which have different morphologies and compositions.

In contrast, uric acid stones are typically radiolucent, which means they do not show up on X-rays, and their appearance is often more varied, typically being not as easily identifiable as the characteristic shapes of calcium oxalate stones. Struvite stones, while also radiopaque, tend to have a more "co