About the Stones

Key	Name	Location	Formula or Type	Description
A	ankerite "Arctic Gold"	Brooks Range	Ca(Fe,Mg,Mn)(CO₃)₂	This golden brown mineral was collected along a small stream running down from an area containing limestone and marble, in the mountains of northern Alaska. It is basically calcite or dolomite mixed with varying amounts of iron, magnesium and manganese. It forms in mineral veins, sometimes along with gold.
B	blue chert radiolarite	Coldfoot	colored SiO₂	This blue stone was found along a popular fishing stream in southern foothills of the Brooks Range, northern Alaska. Chert is a variety of quartz which differs from jasper in that it forms from sediments, often the accumulation of remains of radiolarians, plankton having microscopic silica shells.
C	chalcocite copper sulfide	Wrangell Mts	Cu₂S	This silvery metallic mineral was collected in the early 1990s below tall limestone cliffs at the Bonanza Mine, on a ridge above the Kennicott Glacier, in the Wrangell Mountains. This area contained the richest copper deposit known on earth. Pure chalcocite is 79.85% copper by weight. The mines operated from 1911 until 1938.
@	covellite copper sulfide	Wrangell Mts	CuS	This dark blue metallic mineral was collected in the early 1990s below tall limestone cliffs at the Bonanza Mine, on a ridge above the Kennicott Glacier, in the Wrangell Mountains. This area contained the richest copper deposit known on earth. Pure chalcocite is 79.85% copper by weight. The mines operated from 1911 until 1938.
D	red jasper chalcedony	Talkeetna Mts	colored SiO₂	This dark red stone is called jasper. It is an opaque form of chalcedony (a variety of quartz), colored by impurities. Iron causes hues of red, orange, yellow, green, and brown. Composed mostly of silica, jasper breaks with conchoidal fracture, so was used prehistorically in making stone tools.
E	epidote a sorosilicate	Southcentral	Ca₂(Al,Fe)₃(SiO₄)₃(OH)	This lime green mineral is not uncommon around Alaska. In this case it comes from the Talkeetna Mountains or the Alaska Range. Due to the green color, it is often mistaken for jade. It is classified as a sorosilicate ("soro" meaning "sister"), because its silicate tetrahedrons occur in pairs.
F	"camouflage" "Kenai Camou"	Kenai Mts	metamorphic	This mottled green rock occurs along gold bearing stream in mountains on the Kenai Peninsula. A local miner named it for the swirled patterns resembling his camouflage hunting vest. Metamorphism (exposure to heat and pressure) results in the swirling and mixing of minerals and thus also of colors.
G	green quartzite metaquartzite	Alaska Range	metamorphic	This gray green rock was collected from a small stream in the Alaska Range, a band of mountains containing Denali, the highest peak in North America. Quartzite (or metaquartzite) is metamorphosed quartz or sandstone. Here color is due to the presence of minerals, probably chlorite.
H	hematite quartz "Purple Cow"	Paxson	mostly SiO₂	This white stone with purple specks comes from a glacier near the junction of the Richardson and Denali Highways. It is mostly common quartz, with purple spots and patches caused by iron oxide in the form of the mineral hematite. We gave it the name "Purple Cow", for obvious reasons.
I	fossil ivory wooly mammoth	Interior Alaska	Mammuthus primigenius	This fossil ivory, varying light cream to dark brown in color, comes from the tusks of the long extinct wooly mammoth. They roamed throughout the large unglaciated lowlands, between mountains in what is now the interior of Alaska, during the last ice age, about 10,000 to 40,000 years ago.
J	nephrite jade Alaska State Gem	Kobuk Valley	Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂	This semi-translucent green mineral was extracted many years ago by mining operations east of Kotzebue, north of the Arctic Circle, in southern foothills of the Brooks Range, western Alaska. A semi-precious variety of jade, nephrite is a dense, compact, fibrous mineral from the amphibole group of complex hydrous silicates. Our state gem, it can vary from light to dark, bluish to brownish.
K	black chert flint nodule	Wrangell Mts	mostly SiO₂	This opaque black stone was found in stream deposits from the Wrangell Mountains, where it weathered out of bedrock. Before that, it spent millions of years as a flint nodule within a layer of limestone. Earlier, during the Triassic, the chert and limestone were formed as marine deposits from shells of silica and calcite, respectively.
L	clinozoisite with manganese	Haines	Ca₂Al₃(SiO₄)₃(OH)	This pink mineral comes from the coast along the Chilkoot Inlet, near the town of Haines. It is composed mostly of clinozoisite, a silicate belonging to the epidote mineral group, and is slightly magnetic. Analysis shows that manganese and titanium are also present, probably contributing to the pink color.
M	moss agate dendritic opalite	Healy	SiO₂ with MnO₂	This translucent stone is a mixture of clear to milky chalcedony (opalite), brown jasper and black dendrites, which are moss-like branching growths of the mineral pyrolusite (or manganese dioxide). It was found near the town of Healy, at the eastern end of Denali National Park and just north of the Alaska Range.
N	"neptune gneiss" with nickel ore	Alaska Range	metamorphic	This teal rock comes from the Alaska Range, a wide belt of glaciated mountains which arcs across Alaska and contains Denali, tallest mountain in North America. Gneiss, a metamorphic rock usually banded and gray in color, is bluegreen here due to presence of nickel minerals. The small golden flecks are a form of mica.
O	obsidian volcanic glass	Talkeetna Mts	igneous	This translucent black rock came from deep in the Talkeetna Mountains. Obsidian is volcanic glass, and results when lava is violently ejected from a volcano and cools so quickly that its minerals do not have enough time to grow crystals. Composed mostly of silica, the stone breaks with a conchoidal fracture, and hence was sometimes used prehistorically in making stone tools.
P	pink marble metacarbonate	Brooks Range	metamorphic	This opaque pink and gray rock was collected from a small stream in the Brooks Range, many miles north of the Arctic Circle. Marble comes from the metamorphism of carbonate rocks such as limestone and dolomite. Usually gray and white, marble can be pink in color from dolomite or pigmented particles of chert or clay.
Q	quartz "Stone of Luck"	Southcentral	SiO₂	This white mineral, varying in transparency from glassy clear to cloudy or milky translucent to almost solid opaque, is one of the most common minerals in the world. Sometimes it forms crystals; if the crystals are very small, it is called chalcedony. Here it was collected from southcentral Alaska, either the Alaska Range or the Talkeetna Mountains.
R	rose quartz "Stone of Love"	Alaska Range	SiO₂	This translucent mineral, varying from clear to milky and pink to pale, is colored by trace amounts of the element titanium. It comes from the Alaska Range, a wide belt of glaciated mountains which arcs across the middle of Alaska. The range contains Denali (Mount McKinley), the tallest mountain in North America, rising to 20,320 feet (6194 meters).
S	serpentine a phyllosilicate	Hatcher Pass	Mg₃Si₂O₅(OH)₄	This dark green magnetic mineral comes from Hatcher Pass, a gold mining area in the Talkeetna Mountains near Palmer. It is formed by alteration of dark igneous minerals such as amphibole, olivine, and pyroxene. It is related to and often mistaken for jade, which is harder and denser. It is a classified as a phyllosilicate ("phyllo" means "leaf"), because its silicate tetrahedrons form flat sheets of hexagonal rings.
T	tan jasper chalcedony	Talkeetna Mts	colored SiO₂	This light brown stone is called jasper. It is an opaque form of chalcedony (a variety of quartz), colored by impurities. Iron causes hues of red, orange, yellow, green, and brown. Composed mostly of silica, jasper breaks with conchoidal fracture, so was used prehistorically in making stone tools.
U	"aurora borealis" altered dolomite	Hatcher Pass	metamorphic	This bluegreen rock comes from Hatcher Pass, a gold mining area in the Talkeetna Mountains near Palmer. Due to its color, it was named for the northern lights which often dance in the winter sky above. It is an altered dolomite breccia with quartz, garnierite (green nickel ore), limonite (brown iron oxide), and accessory gold.
V	violet volcanic a porphyry	Paxson	igneous	This dark violet rock with pale spots comes from a small stream near the junction of the Richardson and Denali Highways. It is a porphyry, the result of volcanic activity where magma cools slowly enough for some crystals (the pale feldspars) to form, yet so quickly that other minerals remain in matrix.
W	welded tuff blue volcanic	Talkeetna Mts	igneous	This mottled cyan rock (with red, black, and white grains) has pyroclastic origins, as it was blasted out of a volcano in a violent eruption event. The variously colored grains are fragments of lava (mostly as shades of blue) and other shattered rocks which were mixed and cemented together.
X	augen gneiss with feldspar eyes	Tok	metamorphic	This gray and white rock was the result of metamorphism of granite, under high temperature and high pressure, to form gneiss. Since the white feldspar crystals are larger than usual, they stand out from the banded, darker gray matrix like eyes, and hence the term "augen", which is German for "eyes".
Y	yellow jasper chalcedony breccia	Homer	colored SiO₂	This yellow stone (sometimes also colored red or white, and often with black streaks) is brecciated jasper from Kachemak Bay near the town of Homer. Jasper is chalcedony (a variety of quartz) colored by impurities, in this case iron. The term "brecciated" means that the original stone was naturally broken and later cemented back together by minerals in the matrix.
Z	"blizzard stone" altered gabbro	Palmer	igneous	This magnetic rock, with white calcium feldspar speckles in a black serpentine rich matrix, comes from the Talkeetna Mountains. It began as a gabbro, originating deep under a mid-ocean ridge, but was highly altered by hot circulating seawater at the spreading center, then was scraped off and brought to the surface (and pushed up into the mountains) by the actions of plate tectonics.