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Geology
crystal quartz

All birthstones are minerals but not all minerals are considered gems. We dive in to the facts, legends and history behind each birthstone.

Graphic with "The Big One: Earthquakes in the Pacific Northwest" written on it

We live in earthquake country. Learn about quake science, tsunamis and what you can do to prepare for the Big One in this web feature from 2002.

geologic map of Washington state

An introduction to the geologic history of Washington state.

Duwamish River in 1906

For millennia, the Duwamish River sustained a diverse ecosystem before experiencing a dramatic transformation wrought by human engineering.

Comparative photo of Seattle’s changing landscape

Seattle is one of the most dramatically re-engineered cities in the United States.

Mountain view from the San Juan Islands.

The people who come on these tours of San Juan Island are curious about one thing: stories of people and place. 

Blue topaz is an alternate birthstone for December.

Turquoise is composed of hydrated copper and aluminum phosphate. It forms when circulating water alters other aluminum-rich rocks in desert environments.

Citrine as naturally occurring crystals.

Some citrine actually began as purple amethyst, but heat from nearby molten rock changed it to a warm yellow color.

Opal as it naturally occurs in rock.

The presence of water in the mineral structure allows geologists to determine the temperature of the rock at the time the opal formed.

Sapphire is a form of the mineral corundum.

Sapphire is any form of corundum that is not red, as red varieties are called rubies.

Peridot is a type of olivine.

Peridot is type of olivine, and comes in various shades of green, from light to a brilliant olive green. 

Ruby is a form of the mineral corundum.

Ruby originates from metamorphic rock, and is a variety of the mineral corundum, second only to the diamond in hardness.

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