Rock Identification

Granite

3 different combinations of minerals

Rhyolite

pink to white color/ Llanite blue quartz crystal

Pumice

will float in water

Scoria

will sink in water

Basalt

vesicular basalt has holes/ amygdaloidal basalts holes are filled in

Gabbro

looks like basalt but is more specularite with glossy pieces

Obsidian

glassy texture/mahogany obsidian wood glassy look/ snowflake obsidian white spots on black.

Perlite

small “pearl” of obsidian with grey rock

Chalk

reacts with acid and can write its own name

Coquina

broken sea shells put together, looks like granola, and reacts with acid.

Fossiliferous L.S.

has fossil organisms but is mostly rock/ reacts with acid

Oolitic L.S.

tiny spheroids and reacts with acid

Shale

breaks off in sheets and has a low, dull pitch sound

Sandstone

made up of sand particles sand can come off

Conglomerate/ breccia

natural concrete

Chert/ flint

hardness of 7, it can start a fire

Rocksalt

tastes salty and has crystals

Bituminous coal

alternating layers that are shiny and dull, it burns cold and dirty

Anthracite coal

burns hot and clean

Quartzite

hardest rock we’ve looked at, is glassy and cracked

Marble

reacts with acid, metamorphosized limestone

Serpentine

white layering, dark green rock, soapy feel

slate/ phyllitic

high/ bright pitch flat and platy has layers

Schist

shiny has red/ orange garnet gemstone

Gneiss

zebra striping, augen gneiss has eye shape on it