Igneous rocks are formed through the cooling and solidification of magma or lava and they may form with or without crystallization. Intrusive, or plutonic, igneous rocks form when molten rock (magma) cools underground. Extrusive, or volcanic, igneous rock form when molten rock (lava) cools on the surface.
Rockman's igneous rock specimens are hand broken as opposed to being crushed which helps keep cleavage and fracture characteristics intact and provides freshly broken areas for better examination of the specimens. If you are looking for a specimen that is not listed, please contact us; we may have it in stock or we may be able to locate it. We offer our igneous specimens as 10-packs provided in resealable bags or a large specimen in a cardboard box; except Volcanic ash which is offered as one bag (two different sizes).
We offers the 3 standard sizes of igneous rocks as illustrated:
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Andesite - (gray or medium-brown, with phenocrysts)
- 10 Pack - Small [RI010b]
- 10 Pack - Medium [RI010c]
- 1 Large Sample [RI010d]
Anorthosite (gray, coarse-grained)
- 10 Pack - Small [RI015b]
- 10 Pack - Medium [RI015c]
- 1 Large Sample [RI015d]
Basalt - Compact (gray to black, fine grained, may have a few vesicles)
- 10 Pack - Small [RI020b]
- 10 Pack - Medium [RI020c]
- 1 Large Sample [RI020d]
Basalt - Flood (dark gray to black)
- 10 Pack - Small [RI021b]
- 10 Pack - Medium [RI021c]
- 1 Large Sample [RI021d]
Basalt - Porphyry (hornblende phenocrysts)
- 10 Pack - Small [RI022b]
- 1 Large Sample [RI022d]
Basalt - Vesicular (medium gray, brown or black with multiple vesicles)
- 10 Pack - Small [RI024b]
- 10 Pack - Medium [RI024c]
- 1 Large Sample [RI024d]
Breccia - Volcanic (angular rock fragments in groundmass)
- 10 Pack - Small [RI030b]
- 10 Pack - Medium [RI030c]
- 1 Large Sample [RI030d]
Diabase (medium grained rock, composed mostly of pyroxene & feldspars)
- 1 Large Sample [RI045d]
Diorite (medium grained, black and white)
- 10 Pack - Small [RI050b]
- 10 Pack - Medium [RI050c]
- 1 Large Sample [RI050d]
Felsite (porphyry, hard, gray, light brown to reddish-brown)
- 10 Pack - Small [RI054b]
- 10 Pack - Medium [RI054c]
- 1 Large Sample [RI054d]
Gabbro (coarse-grained, brown to black)
- 10 Pack - Small [RI060b]
- 10 Pack - Medium [RI060c]
- 1 Large Sample [RI060d]
Granite - Pink to Red (medium to coarse-grained)
- 10 Pack - Small [RI074b]
- 10 Pack - Medium [RI074c]
- 1 Large Sample [RI074d]
Granite - White to Gray (medium to coarse-grained)
- 10 Pack - Small [RI076b]
- 10 Pack - Medium [RI076c]
- 1 Large Sample [RI076d]
Granodiorite (white, gray & black, medium to coarse-grained)
- 10 Pack - Small [RI077b]
- 10 Pack - Medium [RI077c]
- 1 Large Sample [RI077d]
Kimberlite (blue-tinged to dark matrix rock with dark porphyritic texture)
- 10 Pack - Small [RI071b]
- 10 Pack - Medium [RI071c]
- 1 Large Sample [RI071d]
Monzonite (medium-grained)
- 10 Pack - Small [RI078b]
- 10 Pack - Medium [RI078c]
- 1 Large Sample [RI078d]
Obsidian - Black (lustrous, conchoidal fracture)
- 10 Pack - Small [RI080b]
- 10 Pack - Medium [RI080c]
- 1 Large Sample [RI080d]
Obsidian - Mahogany (reddish-brown to mostly black, conchoidal fracture)
- 10 Pack - Small [RI085b]
- 10 Pack - Medium [RI085c]
- 1 Large Sample [RI085d]
Obsidian - Snowflake (in black matrix, conchoidal fracture)
- 10 Pack - Small [RI086b]
- 10 Pack - Medium [RI086c]
- 1 Large Sample [RI086d]
Pegmatite (large coarse-grained minerals)
- 10 Pack - Small [RI087b]
- 10 Pack - Medium [RI087c]
- 1 Large Sample [RI087d]
Peridotite (medium-grained, blackish with dark green tint)
- 10 Pack - Small [RI088b]
- 10 Pack - Medium [RI088c]
- 1 Large Sample [RI088d]
Perlite (amorphous volcanic glass - SiO2)
- 10 Pack - Small [RI089b]
- 10 Pack - Medium [RI089c]
- 1 Large Sample [RI089d]
Pitchstone (medium gray to black)
- 10 Pack - Small [RI091b]
- 10 Pack - Medium [RI091c]
- 1 Large Sample [RI091d]
Pumice (light gray to almost black)
- 10 Pack - Small [RI090b]
- 10 Pack - Medium [RI090c]
- 1 Large Sample [RI090d]
Rhyolite (pink, tan or gray)
- 10 Pack - Small [RI100b]
- 10 Pack - Medium [RI100c]
- 1 Large Sample [RI100d]
Scoria (reddish-brown to dark gray)
- 10 Pack - Small [RI110b]
- 10 Pack - Medium [RI110c]
- 1 Large Sample [RI110d]
Syenite (cream to medium gray, medium to large-grained, no quartz)
- 10 Pack - Small [RI115b]
- 10 Pack - Medium [RI115c]
- 1 Large Sample [RI115d]
Trachyte Porphyry (gray, porphyryitic, small to large phenocrysts)
- 10 Pack - Small [RI120b]
- 10 Pack - Medium [RI120c]
- 1 Large Sample [RI120d]
Tuff (light tan, fine-grained with small rock/mineral material in matrix)
- 10 Pack - Small [RI130b]
- 10 Pack - Medium [RI130c]
- 1 Large Sample [RI130d]
Volcanic Ash (light gray, very fine-grained, Mount St. Helens' ash)
- 1 2x2" bag [RI140b]
- 1 3x3" bag [RI140c]