Browse Items (1651 total)

Hand Sample: Aphanitic light gray vesicular pumice. Sample has incredibly low specific gravity due to abundant vesicles. Vesicles range in size from less than 0.1cm to 0.3cm. Some vesicles on cut face appear to be filled in with a lighter material.…

Hand Sample: Lapilli tuff containing pieces of pumice (HA-23) and trachyte obsidian (HA-22) ranging in size from 0.1cm to 1.5cm. Clasts are held together in light-colored ash. Sample surface crumbles when handled. Lapilli describes the size of the…

Hand Sample: Natural surface of sample is dark in color with smooth texture. Cut face reveals blocks of peridotite and dunite held together with a thin layer of lava cement. Sample has high specific gravity.

Hand Sample: Microcrystalline vesicular, dark-gray to black scoria. Vesicle size varies throughout the sample, ranging from larger circular vesicles with a diameter of approx. 1.5 cm on one surface and small vesicles (less than 0.1cm in diameter) on…

Hand Sample: Aphanitic dark gray vesicular basalt. Sample contains numerous vesicles ranging in size from less than 0.05cm to 1.5cm. Individual olivine crystals can also be found throughout the sample.

Hand Sample: Aphanitic dark gray vesicular basalt. Vesicles are common throughout sample and range in size from 0.1 to 3.5cm in diameter. Individual olivine crystals are found throughout the sample and range in size from 0.1 to 0.4cm in length.

Hand Sample: Aphanitic medium gray nephlenite. White intergrowth crystals are common throughout the sample and form long strands (approx. 0.6 - 1cm in length) on sides of sample. Sample contains some melilite.

Hand Sample: Aphanitic light gray nephelinite containing some melilite. Melilite is the white minerals that range in size from 0.1 to 0.5cm. Sample contains numerous small sized (less than 0.05cm) vesicles that are evident on the cut face.

Hand Sample: Aphanitic, pink-black rhyodacite. Sample contains alternating black and dark pink bands across face. Sample does not contain any vesicles or phenocrysts.

Red shale from the Indian River member of the Normanskill formation. This rock contains hematite, chlorite, muscovite, plagioclase, and quartz.

The thin section shows muscovite and biotite with some larger quartz grains visible and minor hematite…

Green shale of the Indian River member of the Normanskill formation. This shale contains muscovite, chlorite, plagioclase, and quartz.

The thin section shows quartz and biotite with some minor opaques.

This rock is from the chlorite zone of the…

The graywacke facies in the Mt. Merino member (where sample 4 also comes from). Graywacke is a hard, dark-colored sandstone. This sandstone represents a similar rock to the protolith for the quartzite of sample 10.

The thin section shows quartz,…

Kink fold in a slate from the Mt. Merino Member.

This rock is from the chlorite zone of the Barrovian metamorphic sequence (low metamorphism).

A highly graphitic slate in the Walloomsac slates. Contains pyrite. This rock also contains biotite, chlorite, muscovite, quartz, ilmenite, and pyrite.

The thin section shows large biotite grains, and chlorite muscovite, and quartz. Fluid…

Schist with sparse garnet. This schist is darker and graphitic. It also contains biotite, chlorite, muscovite, feldspar, and quartz.

The thin section shows several large biotite grains with an included garnet, small quartz grains, muscovite, and…

Schist with coarse chloritoid crystals (up to 1/8 inch) without preferred orientation. These crystals grow across the foliation developed in the schist, but appear deformed. Chloritoid is a silicate mineral made in metamorphism. It also contains…

Schist bearing both staurolite and chloritoid. This marks the first appearance of staurolite in the metamorphic sequence. Also contains garnet, muscovite, chlorite, biotite, feldspar, and quartz. The assemblage in not in equilibrium.

The thin…

Schist with coarse staurolite grains. This outcropping is approximately on the strike of the chloritoid schists (sample 7). Also contains garnet, muscovite, feldspar, and quartz. Presumed to be from the Everett Schist.

The thin section shows…

Metamorphised sandstone with a gray, glassy appearance. From the Paughquag quartzite, a late Cambrian formation. The basal Cambrian quartzite rests on pre-Cambrian gneisses.

The thin section shows quartz and plag with some biotite and grain…

Schist with coarse biotite controlling foliation. Garnets visible in some hand samples. Kyanite blades without preferred orientation--at higher concentration within folds. Possibly from the Walloomsac schist.

The PPL thin section shows biotite,…