Source: Brazil, Burma, India, Madagascar, Russia, Tanzania, and Zimbabwe
Birthstone: June (Alternate: Moonstone, Pearl)
The name "Alexandrite" comes from the stones' ostensible discovery on April 23, 1830, the day that young Russian Czar Alexander Nicolajevitch II had his "comming of age" birthday.
Alexandrite has a unique ability to absorb certain elements of the colour spectrum;
it can look greenish-bluish-grey in daylight and reddish-purple (raspberry red)
under artificial light. Natural alexandrite is very rare.
Due to its extreme rarity, quality specimens of Indian or Brazilian Alexandrite can sell for several thousand pounds per carat.
Natural Alexandrite is very rare. Most alexandrine found on the market today is synthetic. From the late 1800s, synthetic alexandrine was made to give it the characteristic colour-change effect.
Source: Brazil, Uruguay, Zambia
Birthstone: February (Alternate: Onyx)
The name "Amethyst" comes from the Greek word meaning "against drunkenness." This was perhaps due to a belief that amethyst would ward off the effects of alcohol, but most likely the Greeks were referring to the wine-like colour of some varieties of the stone. Amethyst is the purple variety of the mineral quartz and is a popular gemstone. The colour purple has long been associated with royalty, making amethyst jewellery a popular choice among royal families.
A rare bi-coloured variation of citrine and amethyst called "Ametrine" was recently discovery in Bolivia. Ametrine is a naturally occurring variety of quartz that contains both amethyst and citrine.
Amethyst heat treatment is used if the natural colour of the stone is too dark. The heat treatment is used to lighten the colour to a rich purple or change the colour entirely.
Source: Brazil, Kenya, Madagascar, Mozambique, Tanzania, Uruguay, Zambia
Alternate Birthstone: Bloodstone or Green Jasper is also the birthstone of March.
The name "Aquamarine" (Aquamarin German, Aqua marina Spanish) is derived from the Latin phrase "water of the sea", named for its greenish-blue seawater colour. Blue Spinel, a synthetic mineral, is easy and inexpensive to produce, and it is often mistakenly sold as "Synthetic Aquamarine".
Most Aquamarine on the market today is heat treated to bring out the greenish-blue colour that is characteristic of the stone. Yellow-brown or yellow-green stones are heated to 400 to 450 degrees Celsius to bring out a deep blue colour. The resulting colour change of the aquamarine is permanent and difficult to detect.
Source: Brazil, India, Madagascar, Sri Lanka
Birthstone: November (Alternate: Topaz)
The name "Citrine" (Citrin German, Topacio falso Spanish, Citrino Italian) comes from the French word "citron," or "lemon," for its colour. Citrine closely resembles topaz (also a birthstone for November), but is slightly softer, and has less brilliance. Citrine has been used in Greece since the Hellenistic period at the end of the 4th to the end of the 1st century BC. Citrine can permanently change colour if left in direct sunlight for several hours. In ancient times, citrine was carried as a protection against snake venom. It is also thought to aid digestion, and remove toxins from the body.
Naturally occurring citrine derives its golden colour from the presence of iron (Fe3) ions. Purple amethyst will turn to citrine when heated in a kiln for a certain period of time and much of the yellow, gold, or orange citrine on the market today is heat-treated amethyst.
Source: Australia (95%), Mexico, USA ( Idaho)
Birthstone: October (Alternate: Tourmaline)
The name "Opal" (Opale French) is derived from the Sanskrit word "Upala" the Greek word "Opallios", and the Latin word "Opalus", all meaning "precious stone." Opal is found in a wide range in colours that include white, light blue, green, brown, red (Fire Opal), yellow and even black. Over 90% of the world's gem-opal comes from Australia .
Opal is usually cut into a "cabochon" as opposed to facetted. The cabochon cut is used for most opaque gems although highly transparent fire opals can be facetted.
Opal is a soft stone and therefor is occasionally treated or impregnated with oil, plastic, or wax. Being a sedimentary stone, opal has high water content and if allowed to dry out, it can crack or "craze". In a very dry climate, Opals should be stored in a sealed plastic bag along with a damp piece of cotton to prevent dehydration.
Source: Burma (Myanmar), Egypt, Norway, Pakistan, Saudi Arabia, Sri Lanka, USA (Arizona) (Hawaii)
The name "Peridot," (Péridot French) or "Chrysolite" (golden yellow peridot), means "golden stone" in Greek and is also derived from the French word "Peritot", meaning "unclear" due to significant amounts of inclusions in the stone. Peridot was treasured by the Egyptian Pharaohs. Some of Cleopatra's emeralds were actually peridots. In the Middle Ages, people wore peridot to gain foresight and divine inspiration as well as to protect them against evil. Peridot mining dates back some 4,000 years.
Peridot was called "Topazion" until the 18th century when the British renamed it Peridot. A unique peridot specimen is mines in Pakistan and is called "Kashmir Peridot".
Peridot is not usually enhanced or heat-treated but it is occasionally treated with colourless oils, wax, and natural or synthetic resins to fill in voids or surface fractures and to improve appearance or lustre. You should never clean Peridot ultrasonically.