Agate is a name applied to an aggregate of various forms of silica,
chiefly Chalcedony, found in the US, India, Morocco, the Czech Republic, Brazil,
and Africa. Agates are 25-60 million years old.
Brazilian Agate is mined from eroded lava beds in the Brazilian
plateaus. Its rainbow colors are derived mainly from iron.
Crazy Lace or
The whorl patterns in Crazy Lace Agate are embedded hematite and jasper.
Mexico is the main source of this most unusual agate.
Usually, Montana Agate is a translucent Moss Agate from Montana with
pronounced dendritic forms.
Montezuma is a misspelling of Moctezuma. This stone is usually small,
very deeply weathered, and shows the peeling off of the outer bands.
Moss Agate is characterized by tree-like, inclusions of Hornblende.
These agates are often associated with the fertility of plants.
Polka-dot Agate is mined in Oregon and is peppered with distinctive
black or yellow polka-dots.
Rio Puerco (Moss)
This stone is of a red to apricot color with cloud-like moss, and it is
found in Albuquerque.
Some Amber was deposited as long as one million years ago. As a
sticky resin, it oozed from ancient pine trees and entrapped small insects, and
bits of plants, feathers, and other material. Then, the resin was encased in
dirt and debris, and, through a process of heat and pressure, it fossilized to
Amethyst, a coarse-grained variety of the silica mineral quartz, is
valued for its violet color. It is piezoelectric, which means that it is used in
electronic applications. Amethyst is found in the US, Britain, Canada, Brazil,
Mexico, Russia, Sri Lanka, Uruguay, East Africa, Siberia, and India.
Ammonites are an extinct group of marine animals in the phylum
Mollusca and the class Cephalopoda. Their closest living relative is probably
the modern nautilus, whom they resemble. Ammonites first appeared about 400
million years ago and became extinct around the time of the dinosaurs.
Citrine is a variety of quartz ranging in color from light yellow
(its natural form), through orange, to a dark, reddish-brown (its heat-treated
form). Most heat-treated Citrine comes from Brazil, whereas natural Citrine
comes from Russia, France, and Madagascar.
Jasper, found world wide, is an opaque, impure variety of quartz that
is usually red, yellow, or brown.
Picture jasper exhibits a number of variations in formation and
impurities simultaneously, which results in what appear to be scenes or
images in a cut section. Complex mixes of impurities produce wild color
Ocean Jasper is a type of Rhyolite, which is an igneous rock, rich in
silica. Ocean Jasper has been found only along the northwest coast of
Madagascar at the edge of the ocean where it can be seen and collected only
at low tide.
Lapis, also called Lazurite, occurs in various shades of blue, some
types being speckled with white calcite or yellow pyrite. It is not a mineral,
but rather a rock colored by Lazurite. It is mined in Russia, Afghanistan,
Chile, Italy, the US, Egypt, and the Middle East. Denim Lapis is of a slightly
different color blue than Lapis Lazuli.
The Mabe Pearl is a cultured pearl from the oysters of French
Polynesia (Tahiti). It is cultivated in an oyster called the Black-lipped
Oyster, which is capable of producing green, black, and white pearls. These
pearls are their natural color.
Opalized wood is simply wood that has been replaced by opal. Opal is
not a true mineral, nor does it have a crystalline structure. Instead it is a
compound of silica and water.
Peridot, pronounced pear-a-doe, is a yellowish-green gem variety of
olivine. It is mined in Arizona, Burma, Norway, islands in the Red Sea, and
Hawaii. Sometimes, it is found in meteorites. It has been mined for thousands of
years and is said to have been Cleopatra’s favorite gem.
Petoskey stones were formed by the fossilization of an ancient coral,
Heragonaria, which lived in the warm, shallow seas that covered Michigan during
the Devonian, some 350 million years ago. The stones are found along the shore
of lakes Michigan and Huron.
Petrified Wood is real wood that has been turned into stone. Volcanic
ash, deposited on top of primitive conifers that fell into waterways, is a key
ingredient in the petrification process. As the ash decomposed, it released
chemicals that reacted with the wood to form quartz crystal, which. over
millions of years, turned the wood into stone.
PETRIFIED PALM WOOD
Palm wood stone comes from palm trees that lived during the Oligocene
Epoch between 20 and 40 million years ago. The characteristic spotted look of
palm wood is from the rod-like structures within the grain of the wood.
Depending upon the angles of the cut, these structures show up as spots,
tapering rods or lines.
Serpentine is composed of one or more of the three magnesium silicate
minerals: lizardite, chrysotile, and antigorite. It is considered to be the
metamorphosed remains of magnesium-rich igneous rocks from the earth’s mantle.
It varies in color from apple green to black, and it is often mottled with light
and dark colored areas.
Topaz is a gem-quality aluminum silicate mineral. It is transparent
with a vitreous luster. Topaz crystals occur in highly acid igneous rocks and in
metamorphic rocks. Important sources of topaz are in Russia, Siberia, Brazil,
Australia, and Mexico and in New Hampshire, Colorado, and Utah in the US.
Turquoise, one of the oldest known gemstones, is composed chiefly of
hydrated copper and aluminum phosphates. It is a secondary mineral deposited
from circulating waters, and it occurs as granular veins running through a host
rock. It varies in color from sky blue through various shades of green to
greenish and yellowish gray.