From your favorite gemstone to gemstones you've never heard of, we have fun facts and exclusive information in our new and improved gemstone encyclopedia.
Faceted petalite gems and specimens are prized by gemstone and mineral collectors. Petalite's name is derived from the Greek petalos (leaf), referring to its perfect cleavage. Colorless material is common, and large crystals have been mined. Other petalite colors include white to yellow or gray, yellowish green to light green and pink. Crystals range from transparent to translucent and are prized for their good clarity. Faceted gems aren't often seen due to petalite's cleavage planes.
Petrified wood is the fossilized remains of what once was wood. The material became petrified over time by the invasion of minerals into cavities between and within the cells of natural wood. Instead of decaying, the organic materials in the wood were replaced with minerals, primarily silicate of quartz, without changing the original structure of the wood.
Displaying gorgeous deep raspberry pinks, pezzottaite is a relatively new gemstone that has been subject to much confusion due to its similarities with red beryl. Pezzottaite has a variety of misnomer trade names including Madagascan raspberyl, raspberyl and raspberry beryl. Pezzottaite was first thought to be a new variety of beryl. Pezzottaite upon analysis was found to be a new mineral variety, with a trigonal crystal structure and that it contained cesium and lithium, which differed from beryl, making its trade names misleading.
A rare beryllium mineral, phenakite was named in 1833 from the Greek word for "deceiver," alluding to its similar appearance to quartz. Its crystals are predominantly rhombohedral, and less commonly short and prismatic. Phenakite's rarity, hardness, lack of cleavage and high clarity make it a great option for collectors.
Phosphosiderite is a vibrant purple orchid color and is a relative newcomer to the world of gemstones as it was only discovered in the late 19th century. Fine quality phosphosiderite is hard to come by and this opaque gemstone may contain veins of yellow. In addition to purple, phosphosiderite occurs in colors ranging from white, pink, red, violet red and colorless.
Pietersite is a striking variety of chalcedony that comes primarily from Namibia and, more recently, China. It commonly exhibits various shades of color, ranging from blue to gray and red to yellow and brown. Pietersite displays chatoyancy similar to tigers eye quartz.
Natural pink opal has no play of color and is a mixture of opal, palygorskite and chalcedony. Nicknamed the 'pink Andes opal', the soft pinks of this opal are appreciated as an environmentally friendly alternative to conch pearls as well as pink coral. Today, Peru is the major producer of this most feminine opal variety that is often carved into beads and occasionally faceted into gems.
Poldervaartite can be found in a light orange-pink to milky-white color. High-quality poldervaartite specimens are prized by collectors and facetable material is rare.
Pollucite is often found in association with petalite (formally known as castorite). It was named after the twin brothers Pollux and Castor in Greek mythology. It is an important source of cesium. Facet grade material is prized by gemstone collectors and can be found in Afghanistan, Pakistan, Russia, and the United States.
Polymer clay is made from PVC resin and a liquid plasticizer. It is pliable until baked in an oven. Jewelers use polymer clay to create colorful beads, pendants, earrings, and bracelets in fanciful designs. Since the material can be molded into any shape, cut with simple tools, and embellished with paint, the only limit to its use is the artist’s imagination.
Prase is a dull green to yellowish green variety of chalcedony, a cryptocrystalline quartz. It is commonly fashioned en cabochon to show off its leek-green color. Prase can be confused with chrysoprase since they are very similar in appearance, but a darker, less saturated color is typically indicative of prase.
A pastel dream, this variety of quartz boasts a beautiful soft green color. Sometimes incorrectly referred to by the misnomers "green amethyst" or "lime citrine," prasiolite is rarely found in nature, so most material available on the market is produced by heating or irradiating amethyst. Prasiolite is an exciting gem in that it is readily available in large sizes with high transparency and great durability.
Prehnite is the first gemstone named for a person. It was named in honor of Colonel Hendrik Von Prehn, the Dutch mineralogist credited with its discovery in the 1700's in South Africa. Also, prehnite was the first mineral to be named and described from South Africa, long before the country became an important source for precious gems, including diamond. Many specimens of this gem have an interesting luminous quality, with a vitreous to greasy luster. With color ranging from pale green to a pale yellowish green and a hardness of 6 - 6.5, Prehnite is considered to be fairly sturdy and long wearing when set in jewelry.
Preseli Bluestone is found in the Preseli Hills located in Pembrokeshire in western Wales. Preseli Bluestone is spotted Dolerite which is a type of igneous rock that contains spots or clusters of plagioclase feldspar that make each distinctively different from the next. It is a medium-grained, heavy rock that is harder than granite. Preseli Bluestone was used in the construction of the inner rock circle at Stonehenge. It is widely believed these multi-ton stones were carried nearly 200 miles from the Preseli Hills in Wales to Stonehenge around 2300BC during the third phase of its construction and aligned to the summer solstice. Perseli bluestone tools, such as axes, that were made by ancient civilizations have been found all over the British Isles.
The name Psilomelane was discredited as a distinct mineral variety but the name is still used as group name for hard black manganese oxides of which Romanechite and Hollandite are components. Psilomelane means smooth and black in Greek which aptly describes its appearance. It is often found in botryoidal masses with submetallic luster.
Pyrite has a shiny golden-yellow color and a metallic luster. Its name comes from the Greek word pyr, meaning "a gemstone that strikes fire," due to the sparks produced when pyrite strikes iron. While pyrite has a history of being mistaken for gold, it is differentiated by pyrite's lighter, tougher, broken-faced grains. You may hear pyrite called by its nickname "fool's gold." Marcasite is a polymorph of pyrite. It has the same chemistry, but a different crystal structure. In the jewelry trade, the names pyrite and marcasite are often used interchangeably.
Pyromorphite is a member of the apatite family of minerals. Faceted stones are very rare and its colors are usually brown, green, orange, yellow, colorless, gray and white. Pyromorphite was named in 1813 from the Greek words for "fire" and "form" because, after being melted, the mineral will take on a crystalline shape upon cooling.
Hear the word "garnet," and what invariably comes to mind is the image of the deep red pyrope garnets belonging to the pyralspites family. Pyrope comes from the Greek words pyr and ops, meaning "fire eye." The rich reds are both affordable and beautiful, perfect for not only gemstone collections, but jewelry as well.
Among America's rarest and most stunning pearls, quahog pearls were first valued by Native Americans along the coast of New England. This non-nacreous calcareous concretion forms in colors from white to brown, to purple and lilac in round, button and teardrop shapes. Such pearls are typically collected by fishermen as a result of harvesting the meat of the shellfish.
Quartz is the name of a large group of minerals comprised of silicon dioxide. Quartz is the most abundant mineral on the Earth’s surface, and it can be found on all seven continents. It is best known as its gemstone varieties Amethyst, Citrine, and Rock Crystal Quartz. Quartz crystals are distinctive six-sided prisms with six-sided pyramid terminations. Quartz specimens are attractive and sought after as decorative items.
Quartzite is a metamorphic rock formed when sandstone, which is composed of tiny grains of quartz, is subjected to heat and pressure under Earth’s surface, fusing the sand grains together. The result is an extremely durable rock that can also be dyed to attractive colors.
Adularescent labradorite with a multi-colored glow is sometimes called rainbow moonstone. Rainbow moonstone is colorless and highly transparent and it displays an amazing optical phenomenon called adularescence. Labradorite is a plagioclase feldspar and a member of the triclinic crystal system. Internally repeating feldspar layers scatter the light that enters the stone creating a mystical glow reminiscent of moonbeams. This glow comes to life, rolling across the gems surface, when it is moved.
One of nature's more exotic treasures, rhodochrosite is a manganese carbonate that gets its name from two Greek words, rhodon meaning “rose” and chros, meaning “color.” This is a fitting name, indeed, as its finest colors range from very pale pink, to deep orangey red. Yellow to brown crystals are also known. Rhodochrosite comes in transparent, semi-translucent, and opaque varieties. Semi-translucent to opaque rhodochrosite is often carved or cut en cabochon and typically displays "bacon strip" or "bull's eye" patterns.
Unusually striking, rhodolite is a naturally occurring blend of almandite and pyrope garnet. While raspberry and grape are the most prized colors, rhodolite is also found in shades of purplish red to reddish purple. The name is derived from the Greek rhodon, meaning “rose,” and lithos, meaning “stone.” Rhodolite is typically found as water-worn pebbles in alluvial deposits, but it is also occasionally mined directly from host metamorphic rock. Tough, durable, never enhanced and easily cleaned, rhodolite is ideal for jewelry. Due to its bright transparent clarity, rhodolite is often cut into fantasy shapes.