Black lung diseaseBlack lung disease (BLD), also known as coal-mine dust lung disease, or simply black lung, is an occupational type of pneumoconiosis caused by long-term inhalation and deposition of coal dust in the lungs and the consequent lung tissue's reaction to its presence. It is common in coal miners and others who work with coal. It is similar to both silicosis from inhaling silica dust and asbestosis from inhaling asbestos dust. Inhaled coal dust progressively builds up in the lungs and leads to inflammation, fibrosis, and in worse cases, necrosis.
OnyxOnyx primarily refers to the parallel-banded variety of chalcedony, an oxide mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands; agate has curved bands while onyx has parallel bands. The colors of its bands range from black to almost every color. Specimens of onyx commonly contain bands of black and/or white. Onyx, as a descriptive term, has also been applied to parallel-banded varieties of alabaster, marble, calcite, obsidian, and opal, and misleadingly to materials with contorted banding, such as "cave onyx" and "Mexican onyx".
Orthorhombic crystal systemIn crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a rectangular base (a by b) and height (c), such that a, b, and c are distinct. All three bases intersect at 90° angles, so the three lattice vectors remain mutually orthogonal. There are four orthorhombic Bravais lattices: primitive orthorhombic, base-centered orthorhombic, body-centered orthorhombic, and face-centered orthorhombic.
Silicic acidIn chemistry, a silicic acid (sɪˈlɪsɪk) is any chemical compound containing the element silicon attached to oxide () and hydroxyl () groups, with the general formula or, equivalently, . Orthosilicic acid is a representative example. Silicic acids are rarely observed in isolation, but are thought to exist in aqueous solutions, including seawater, and play a role in biomineralization. They are typically colorless weak acids that are sparingly soluble in water.