Table T5. Igneous texture/structure definitions and abbreviations.

Phenocryst percent:
a Aphyric <1%
sp Sparsely phyric 1%-2%
mp Moderately phyric 2%-10%
hp Highly phyric >10%

Groundmass crystallinity:
c Holocrystalline 90%-100% crystals
hc Hypocrystalline 50%-90% crystals
hyh Hypohyaline 10%-50% crystals
G Hyaline 0%-10% crystals

Grain size:
pc Phanerocrystalline Phaneritic
cg Coarse grained >5 mm
mg Medium grained 2-5 mm
fg Fine grained 1-2 mm
ap Aphanitic <1 mm
mc Microcrystalline <0.5 mm (= aphanitic)
cc Cryptocrystalline Not visible under binocular microscope (= aphanitic)

nov Nonvesicular <1%
spv Sparsely vesicular 1%-5%
mov Moderately vesicular 5%-20%
hiv Highly vesicular >20%

Alteration log:
v Veins
f Unaltered <2%
s Slight 2%-10%
m Moderate 10%-40%
h High 60%-80%
vh Very high 80%-95%
co Complete 95%-100%

Mineral form:
e Equant
t Tabular
b Bladelike or lathlike

Vesicle type and vesiculation structure:
ve Vesicles
vd Diktytaxitic texture
pv Pipe vesicles Hollow
sv Segregation vesicles
vc Vesicle cylinder Filled with vesicular segregation material
hvs Horizontal vesicle sheets Segregation veins; filled with vesicular segregation material
mv Megavesicles Domed roof and flat floors, may have segregation material at their base
vz Vesicular zone >10 vol% macroscopic vesicles