Monoclinic

2/m (C2h)

三条不等长晶轴，两条成90度，一条倾斜 (a ≠ b ≠ c, α = γ = 90°, β ≠ 90°)

单斜晶系具有三条不等长的晶轴，其中一条轴倾斜于另外两条。这是矿物中最常见的晶系，晶体通常呈柱状或板状习性。包括正长石、单斜辉石、石膏、绿帘石和许多角闪石。

The monoclinic crystal system is the most common crystal system for minerals, hosting approximately 32% of all known species. Its three unequal axes include one oblique angle (a ≠ b ≠ c, α = γ = 90°, β ≠ 90°), creating a characteristic 'leaning' appearance. The slight departure from perpendicularity gives monoclinic crystals their distinctive tilted geometry, readily visible in minerals like orthoclase feldspar and gypsum.

Symmetry

Monoclinic symmetry requires one two-fold rotation axis (the b-axis) and/or one mirror plane perpendicular to it. The oblique β angle (typically 90-120°) breaks the rectangular symmetry of the orthorhombic system. The system contains 3 crystal classes: prismatic (most common, with 2/m symmetry), sphenoidal, and domatic. The characteristic 'clinopinacoid' face ({010}) is perpendicular to the unique b-axis. Twinning is extremely common in monoclinic minerals, with contact twins (like gypsum's 'swallowtail' twins) and penetration twins (like orthoclase's Carlsbad twins) being classic examples.

著名矿物

The feldspars — the most abundant mineral group in Earth's crust — include monoclinic members like orthoclase and sanidine (potassium feldspars). Gypsum (CaSO₄·2H₂O) forms transparent 'selenite' crystals up to 12 meters long in Mexico's Cave of the Crystals. Augite and hornblende, the most common pyroxene and amphibole respectively, are monoclinic and abundant in igneous and metamorphic rocks. Epidote forms distinctive pistachio-green prismatic crystals. Malachite's rich green color and banded patterns make it one of the most recognizable monoclinic minerals, prized for ornamental use since ancient Egypt.

矿物 (10)

Biotite

K(Mg,Fe)3(AlSi3O10)(OH)2

09 Silicates

Azurite

Cu3(CO3)2(OH)2

05 Carbonates and Nitrates

Muscovite

KAl2(AlSi3O10)(OH)2

09 Silicates

Wolframite

(Fe,Mn)WO4

07 Sulfates, Chromates, Molybdates, and Tungstates

Staurolite

Fe2Al9Si4O23(OH)

09 Silicates

Talc

Mg3Si4O10(OH)2

09 Silicates

Feldspar (Orthoclase)

KAlSi3O8

09 Silicates

Gypsum

CaSO4 · 2H2O

07 Sulfates, Chromates, Molybdates, and Tungstates

Malachite

Cu2(CO3)(OH)2

05 Carbonates and Nitrates

Epidote

Ca2(Al,Fe)3(SiO4)(Si2O7)O(OH)

09 Silicates

常见问题

What is the Monoclinic crystal system?
单斜晶系具有三条不等长的晶轴，其中一条轴倾斜于另外两条。这是矿物中最常见的晶系，晶体通常呈柱状或板状习性。包括正长石、单斜辉石、石膏、绿帘石和许多角闪石。
What minerals crystallize in the Monoclinic system?
There are 10 minerals that crystallize in the Monoclinic crystal system on MineralFYI.
What symmetry does the Monoclinic system have?
The Monoclinic crystal system has 2/m (C2h) symmetry.
What are the axes of the Monoclinic crystal system?
The Monoclinic system is characterized by 三条不等长晶轴，两条成90度，一条倾斜 (a ≠ b ≠ c, α = γ = 90°, β ≠ 90°).