Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Is glacier ice a type of rock?
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H2O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is a single, six-sided (hexagonal) crystal with a central core and six projecting arms. The metamorphism process is driven by the weight of overlying snow. During metamorphism, hundreds—if not thousands—of individual snowflakes recrystallize into much larger and denser individual ice crystals. Some of the largest ice crystals observed at Alaska’s Mendenhall Glacier are nearly one foot in length.
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Related
Are today's glaciers leftovers from the Pleistocene ice age?
How do we know glaciers are shrinking?
How old is glacier ice?
How much of the Earth's water is stored in glaciers?
How would sea level change if all glaciers melted?
Do ice worms exist?
Why is glacier ice blue?

Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.

Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.

Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Sea ice in the Chukchi Sea in 2013.
Sea ice in the Chukchi Sea in 2013.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Image of sea ice along the Arctic Ocean.
Digital-image processing and image analysis of glacier ice
State of the Earth’s cryosphere at the beginning of the 21st century : glaciers, global snow cover, floating ice, and permafrost and periglacial environments
Fifty-year record of glacier change reveals shifting climate in the Pacific Northwest and Alaska, USA
Satellite image atlas of glaciers of the world — North America
Glaciers: A water resource
Related
Are today's glaciers leftovers from the Pleistocene ice age?
How do we know glaciers are shrinking?
How old is glacier ice?
How much of the Earth's water is stored in glaciers?
How would sea level change if all glaciers melted?
Do ice worms exist?
Why is glacier ice blue?

Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.

Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.

Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Sea ice in the Chukchi Sea in 2013.
Sea ice in the Chukchi Sea in 2013.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Image of sea ice along the Arctic Ocean.