rhombic

When treated with hydrochloric or acetic acid they slowly dissolve and rhombic crystals of uric acid appear.

Upon addition of acetic acid they dissolve, and rhombic plates of uric acid appear.

The crystals are dark-brown rhombic plates lying singly or in crosses, and are easily recognized (Fig. 83).

Yellowish or brown, needle-like or rhombic crystals of hematoidin (Fig. 32) may be seen after hemorrhage into the bowel.

Aragonite, a mineral formed of calcium carbonate crystallized in the rhombic system; specific gravity 2.94 (compare Calcite).