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Continue ShoppingGemstone Glossary F
Faden Quartz – Tabular quartz crystals that have white thread like lines throughout it. The name Faden comes from the German word for fiber, based on the stone’s patterning. It is widely believed that Faden Quartz’ unique shape happens by the earth’s movement actually breaking the crystals and then healing and continuing to grow, the crystals create uneven step like layers.
Feldspar – Feldspar is the name for the group of minerals containing alumina and silica. Feldspar is the single most plentiful mineral on earth, and includes such minerals as Labradorite and Amazonite. Feldspar is used in many applications including glass flux, paint filler, ceramics and much more.
Fire Agate – Fire Agate is an oxide mineral of chalcedony. It can be found in the Southwestern United Stated and Mexico. Fire Agate has a deep, chocolate brown-reddish body and can display an iridescent palette of colors including red, gold, green, blue and rarely purple. Its formation is botryoidal and it has a waxy, opaque finish.
Fire Opal – Fire Opals are a cream Opal with a milky iridescence and no crystalline structure that display colors of yellow, red and orange and sometimes have a bright green flash. Fire opals generally do not exhibit a play of color, and are often referred to as jelly Opals. The most common source for these Opals is Mexico, though they are found in a few select locations around the world.
Flint Stone from the Baltic Sea – Flint is a hard quartz mineral that was used to create tools in the stoneage and can be used to create sparks to ignite fire. The Baltic variety of flint is greyish with a white crust, creating depth when used for carvings.
Fluorite – Fluorite is a halide mineral that is fluorescent, a property whose name originated from the gemstone itself. While Fluorite is actually colorless, it is often seen in purple, blue, and green as well as many other colors or with multi colored banding caused by impurities within the stone. Fluorite is not only used in the jewelry industry, but also as an iron smelting material.
Fossil Bone – Fossil bones can be of various types and are preserved in petrified form ranging in age between 10,000 years and 4 billions years old.
Fossil Coral – Fossil coral is actually agatized coral in which agate has replaced the coral as it fossilized. Fossil coral can range between cream to yellow, brown to red and even dusty blue and displays floral like patterns.
Fossil Fish – Fossil fish have been found in a variety of species. Commonly found are herring in a limestone matrix, these fossil fish are an orange-tan hue and can be just 1.5 cm long.
Fossil Mammoth Tusk – Fossil mammoth ivory is believed to be available in abundance, though its location in permafrost and ice make it difficult to search for. Fossil mammoth ivory that is found in Siberia can only be searched for between June and September when the snow is melted as the terrain is too treterous in other months. Perfect for carvings and collectibles, these fossils can be a great focal point in jewelry.
Fossil Peanut Wood – Fossi peanut wood is a fossilized driftwood of confier trees found in Australia in which tunnels have been carved out by extinct cretaceous clams. As these tunnels were created, the wood would become waterlogged and sink to the ocean floor. As this dark brown to black wood fossilized, the tunnels would fill in from a white sediment of siliceous shell layer, creating peanut color and shaped patterns in the wood.
Fossil Sea Shell – Fossil sea shells can be found in deserts and can occur from oyster shell, nautilus shells or other extinct marine creatures.
Fossil sea urchins are echinoids, a five point radial symettry shell. Holaster from the crestacious period are quite uniform in shape and small in size, making them perfect for use in beach style jewelry.
Fossil Shark Tooth – Fossil shark teeth generalize a large list of types such as mako, reef, bull, megaladon or other shark and can be as small as a quarter of an inch up to a full seven inches in size.
Fossil Turtle Shell – Fossil turtle shells can be of a variety of types of extinct turtles, such as the soft shell turles of the late cretaceous period. These shells are generally varying shades of brown and have a textured surface.
Freshwater Pearl – Cultured freshwater pearls are created using freshwater mollusks. Most of these pearls are dyed or bleached to achieve a desired color and they are rarely round.
Fuchsite – The green, chromium rich variety of Muscovite, or Mica; a silicate mineral. Fuchsite is a pale mint to pistachio toned green and sometimes has a