What does anorthic mean?
Anorthic is a technical adjective used in crystallography to describe crystals belonging to the least symmetrical of the seven crystal systems, now more commonly called the triclinic system. In an anorthic crystal, the three crystallographic axes are all of different lengths and meet one another at angles that are not right angles, giving such minerals the lowest possible symmetry. The word derives from Greek roots meaning 'not straight', a fitting description of these oblique, asymmetrical structures. Although modern scientists overwhelmingly prefer the term 'triclinic', 'anorthic' persists in older mineralogical literature and lives on indirectly in the name of the feldspar mineral anorthite, which crystallizes in this system. Readers are most likely to encounter it in historical scientific texts, gemmological references, or discussions of classical crystallography, where it serves as a concise label for nature's most lopsided crystalline arrangements.
adjectiveRelating to or designating the anorthic (triclinic) crystal system, in which crystals have three unequal axes, none of which are at right angles to one another. It is a technical term used chiefly in crystallography and mineralogy.
- Of or relating to the anorthic (triclinic) crystal system, characterized by three unequal axes meeting at oblique angles.
"Feldspar commonly crystallizes in the anorthic system, its three axes of unequal length meeting at oblique angles."
"Kyanite is a classic example of a mineral belonging to the anorthic system."
"In older mineralogical texts, the anorthic system was described as having axes of unequal length inclined at oblique angles."
'Anorthic' literally means 'not straight' — Greek roots naming crystals whose three axes refuse to meet at right angles.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anorthic
The word 'anorthic' comes from Greek roots: the prefix 'an-' (meaning 'not') combined with 'orthos' (meaning 'straight' or 'right'), so it literally signifies 'not right-angled'. It entered English scientific vocabulary in the nineteenth century as crystallographers classified crystals into systems based on axial relationships. It shares its root with words such as 'orthodox', 'orthography', and 'orthogonal', all of which derive from the same Greek notion of straightness or correctness.
Related word forms
How anorthic is actually used
A technical term confined to crystallography and mineralogy; rarely encountered outside scientific literature. In modern usage, 'triclinic' is the more common equivalent, and 'anorthic' survives mainly in older texts and as the source of the mineral name 'anorthite'.
Easily confused with anorthic
Anorthite is a specific calcium-rich feldspar mineral, whereas 'anorthic' describes the triclinic crystal system in which such minerals crystallize.
Anorthosite is a coarse-grained igneous rock composed largely of plagioclase feldspar, while 'anorthic' refers only to the crystallographic system.