Agate, a form of chalcedony, is an excellent gem material because
of its hardness, attractive colors and ability to take a brilliant
polish. Available in a variety of patterns, agate ranges from
transparent ot opaque, and occurs in many colors. Agate is named
after the Achates River in Sicily (now known as the Drillo River)
which remains a major source of this gem. Agate was valued by ancient
civilizations, the Egyptians used it before 3000 B.C. and it was
discovered with Stone-Age man in France (25,000 - 16,000 B.C.).
. Mohs Hardness: 6.5 - 7
Amber is an organic gem. It is the hardened, fossilized sap
or resin from ancient pine trees. Its name probably stems from
the Arabic ambar (meaning ambergris, a substance from a sperm
whale used to make perfume). Amber has been treasured and used
for centuries, beads, pendants, buttons and other ornamental
objects have been made from this gem.
Amber often contains bubbles and other inclusions such as
small plant or animal fossils. Its color and transparency can
vary, but the most common colors are orange, yellow and brown.
. Mohs Hardness: 2 - 2.5
. Color: Golden yellow to orange.
Bloodstone is a type of charlcedony also known as heliotrope;
the name comes from the Greek helio (sun) and trepein (turning).
Iron minerals cause the characteristic red and brown spots, which
are said to resemble blood drops.
. Mohs Hardness: 6.75 - 7
. Color: Varying shades of dark green with red and brown spots.
Carnelian, a type of chalcedony, gets its name from the Latin
cornum (carnel berry or carnelian cherry). Its red color is
due to the presence of iron. This lovely gemstone was popular
in ancient Egypt. It has been carved into insigna seals because
it won't stick to wax. Today, carnelian is worn for good luck in
the Near East.
. Mohs Hardness: 6.50
. Color: Light to dark reddish brown.
Treasured by many cultures for thousands of years, coral
is one of the world's few organic gems. Coral is the
branching exoskeleton of polyps, tiny marine animals that
live in huge colonies, these polyps exude calcium carbonate
(mineral calcite) deposits to create a protective home. Many
colors and varieties of coral are found in warm coastal waters
around the world.
. Mohs Hardness: 3 - 4
Oxblood coral is the most valued red coral. The oldest known coral
used for jewelry and other ornamental objects, red coral was used by
the ancient Mesopotamians in 3000 B.C.
. Color: Deep red.
Hematite is iron oxide, a common iron ore. Its name comes
from the Greek aima, or ema (blood, which refers to the blood-
red color of powdered hematite.
Used as an ornamental stone since early times, hematite has
sometimes erroneously been called black diamond. The ancient
Egyptians used it to treat hysteria, to reduce inflammation
and to place in tombs. Engraved hematite seals have been found
in the ruins of ancient Babylon.
. Mohs Hardness: 6 - 6.50
. Color: Blackish grey with a metallic lustre.
Jasper is a variety of microscopically crystallized quartz
(chalcedony) that is heavily pigmented with colorful minerals.
Many of the red to ochre colors are due to iron oxide in the
stone. Jasper has been used for many centuries as a gemstone
and for ornaments, sculptures and carvings. It is hard and
durable, and it polished well.
. Mohs Hardness: 7
. Color: Patterned with spots and patches of olive green, rust,
pink, ochre yellow, orange, brown and black.
. Color: Clay red, with a slight matrix.
Lapis Lazuli is composed of lazurite, pyrite and calcite. This
vivid blue gemstone gets its name from the Arabic allazward (meaning
sky or blue). Lapis has been used since before 3100 B.C.
Ancient Egyptians were particularly fond of the stone, they used
powdered lapis pigment for medicines, cosmetics (the first eye
shadow) and paintings. They also believed lapis to be sacred
and buried it with their dead to protect and guide them in the
afterlife. Afghanistan remains a major source for this gemstone.
It's also one of the oldest sources, as lapis has been mined there
for more than 6000 years.
. Mohs Hardness: 5 - 6
. Color: Royal blue