Hypocrystalline – crystals + glass

glassPlane light

X polarized light

Holocrystalline – 100% crystals

0 5 10 mm

Fine-grained (<1 mm)

Medium-grained (1-5 mm)

Coarse-grained (5-30 mm)

Aphanitic

Phaneritic

1mm

1mm1mm

Equigranular Seriate/Hiatal

Porphyritic

Plagioclase Porphyritic or Plag-phyric

Subhedral AnhedralEuhedral

Subpoikilitic PoikililticAmeboidalOikocryst Chadacyrst

Embayed Skeletal

Spinifex Dendritic Radial

Intergranular Subophitic Ophitic

Intersertal Pyroclastic

glass

olivine

Philip Farquharson, 2004 www-odp.tamu.edu/

Foliation – alignment of elongate minerals in a common plane

Qualifiers: Non-foliated – random orientation of elongate minerals

Poorly foliated – less than 50% aligned within 10° of common plane

Moderately foliated – 50-75% aligned “

Well foliated - > 75% aligned “

Trachytoid – alignment in fine-grained volcanic rocks

Radiate

Micrographic/GranophyricSutured Symplectitic

Corona

Biotite on Oxide Hornblende on Orthopyroxene Clinopyroxene on Olivine

Rapakivi - Alkali Feldspar mantled by Plagioclase Feldspar

Peritectic Reaction RimOl+melt = Opx

Exsolution in Inverted Pigeonite

< Blebby

Lamellar >

Linked Exsolution between Inverted Pigeonite (IP) and Augite (Cpx)

IP

IPBio

Feox

Cpx

Perthite – Na-plagioclase exsolved from K-feldspar

Oxide Needles in PlagioclaseOxide Exsolution and Epitaxial Biotite in Augite rimming Olivine

Plagioclase SymplectitePl>CaPl+Opx

Olivine Symplectite

Ol>Opx+Mt

Simple Twin (in Cpx) Polysynthetic Twinning(Albite Twinning in Pl)

Textural and Modal Layering in Gabbro Flow banding in Rhyolite

Amygdules in Basalt