You Searched For: Igneous Rocks

ward’s sciencewardsci.com800-962-2660 Greenstone Type: Metamorphic; regional. Texture/Appearance: Fine-grained massive or compact; generally non-schistose. Color: Dark green. Mineralogy/Chemistry: Mainly composed of chlorite actinolite epidote and...

wardsci.com 800-962-2660 Marble Type: Metamorphic; regional and contact. Texture/Appearance: Fine to coarse-grained; granoblastic to saccharoidal. May appear patched or with streaks or banding that is deformed. Color: Variable commonly white pink ...

wardsci.com 800-962-2660 Sphalerite (ZnFe) S Crystallography: Isometric; 43m. Crystals usually tetrahedral or dodecahedral and often distorted and complex; rough curved faces common. Usually in cleavable masses coarse to fine granular. Physical Pr...

+ward’ssciencewardsci.com800-962-2660 Anorthoclase (Na K) AlSi3 O8 (Feldspar Group) Crystallography: Triclinic; 1. Twinning common. Physical Properties: Cleavage: Principle cleavage at right angles or very close to 90°. Fracture uneven; brittle. H...

ward’s sciencewardsci.com800-962-2660 Hornfels Type: Metamorphic regional. Texture/Appearance: Homogeneous; dense fine-grained. Granoblastic; may have porphyroblasts or any of the minerals present. Color: Varies; light to dark. May be pink brown g...

ward’s sciencewardsci.com800-962-2660 Corundum Al2O3 Crystallography: Hexagonal-R; 32/m. Crystals commonly tabular on {0001} or prismatic {1120}; often rude barrel-shaped crystals. Usually massive; coarse or fine granular. Physical Properties: Cle...

wardsci.com 800-962-2660 Topaz Al2SiO4 (FOH)2 Crystallography: Orthorhombic; 2/m2/m2/m. Crystals commonly prismatic with vertical prism faces often striated; also in crystalline masses or granular. Physical Properties: Cleavage: {001} perfect. Fra...

wardsci.com 800-962-2660 Forsterite Mg2 Si O4 (Olivine Group) Crystallography: Orthorhombic; 2/m2/m2/m. Rarely in small equidimensional or tabular crystals; usually in granular masses and as rounded grains. Physical Properties: Cleavage: {101} ind...

+ward’ssciencewardsci.com800-962-2660 Augite (CaNa) (MgFeAlTi) (SiAl)2 O6 (Pyroxene Group) Crystallography: Monoclinic; 2/m. Commonly prismatic crystals with rectangular cross-sections or in granular crystalline masses. Physical Properties: Cleava...

+ward’ssciencewardsci.com800-962-2660 Anorthite CaAl2Si2O8(An90-100) (Feldspar Group) (see also Plagioclase) Crystallography: Triclinic; 1. Crystals usually prismatic parallel to c-axis; twinning as in albite. Commonly massive cleavable with granu...

+ward’ssciencewardsci.com800-962-2660 Ilmenite Fe+2 Ti O3 Crystallography: Hexagonal-R; 3. Crystals usually thick tabular with prominent basal planes and small rhombohedral truncations. Commonly in thin plates massive or compact; also in grains or...

wardsci.com 800-962-2660 Pyrrhotite Fe1-xS (x = 0 - 0.17) Crystallography: Monoclinic; 2/m (below about 250°C). Hexagonal; 6/m3/m2/m for high tempera- ture forms. Crystals rare usually tabular to platy on {0001}. Also massive granular. Physical Pr...

+ward’ssciencewardsci.com800-962-2660 Tuff Type: Igneous; extrusive (pyroclastic). Texture/Appearance: Clastic texture with angular rock and mineral fragments and lapilli mixed with fine-grained volcanic ash partly cemented by sedimentary material...

wardsci.com 800-962-2660 Peridotite Type: Igneous; intrusive. Texture/Appearance: Medium to coarse-grained; massive granular sometimes porphyritic. Color: Medium gray to greenish-gray. Mineralogy/Chemistry: Ultramafic with mafic minerals greater t...

+ward’ssciencewardsci.com800-962-2660 Diabase Type: Igneous; intrusive. Texture/Appearance: Often porphyritic; characterized by an ophitic groundmass where intersecting plagioclase laths are partially or completely enclosed by pyroxene. Massive wi...

+ward’ssciencewardsci.com800-962-2660 Diorite Type: Igneous; intrusive. Texture/Appearance: Massive generally medium-to-coarse grained; subhedral equigranular to por- phyritic. Differences in color and grain size are common with orbicular structur...