Carnelian is a brownish red to orange, translucent to opaque variety of chalcedony. Carnelian is probably named after the the kornel cherry because of its colour. It is sometimes known as cornelian.
Carnelian has been used for decorative purposes by humans for thousands of years. Wikipedia tells us: “The bow drill was used to drill holes into carnelian in Mehrgarh between 4th-5th millennium BC. Carnelian was recovered from Bronze Age Minoan layers at Knossos on Crete in a form that demonstrated its use in decorative arts; this use dates to approximately 1800 BC. Carnelian was used widely during Roman times to make engraved gems for signet or seal rings for imprinting a seal with wax on correspondence or other important documents. Hot wax does not stick to carnelian. Sard was used for Assyrian cylinder seals, Egyptian and Phoenician scarabs, and early Greek and Etruscan gems. The Hebrew odem (translated sardius), the first stone in the High Priest’s breastplate, was a red stone, probably sard but perhaps red jasper.”
Carnelian is thought to aid with concentration, and by keeping one focused on the here and now and not on past experiences. Carnelian is believed to be calming and grounding, and encourages initiative and determination.
Carnelian is understood to improve circulation, aid with problems of the liver, bladder, kidneys and spleen and with male impotency, and to increase appetite. It is believed to help with PMS as well as sexual anxiety.
Carnelian is beautiful – the range of colour from reddish brown through to almost yellow is so vibrant!
I have some gorgeous carnelian available in my gemstone collection. If you find a stone that appeals to you and you’d like to have it set in a ring or a pendant, let me know – I’d love to create something beautiful for you.
Serpentine is the name given to various minerals found in serpentinite rocks. These are used as a source of magnesium and also in industry, and as a decorative stone. The Irish Connemara marble is a form of serpentine.
Serpentine has been used since ancient times to guard against disease and sorcery. It is believed to provide protection against venomous creatures such as snakes and insects. It is thought to balance mood swings, and to promote the ability to solve conflicts peacefully.
Serpentine is beautifully offset by silver I think – it’s my current favourite stone!
I have some serpentine in my gemstone collection. If you find a stone that appeals to you and you’d like to have it set in a ring or a pendant, get in touch – I’d love to create something beautiful for you.
Lapis Lazuli has been mined in Afghanistan for over 6,000 years.
(image credit Philippe Giabbanelli)
Lapis is the Latin word for ‘stone’, and lazuli comes from the Latin ‘lazulum’ which was derived the name of the stone in Persian. The name of the stone came to be associated with its color – the word azure comes from lapis lazuli.
(image credit Parent Géry)
Lapis was long ground up to make the pigment ultramarine, which was widely used during the Renaissance in frescoes and oil painting (this method was replaced in the 19th century with a synthetic compound.)
(image credit Walters Art Museum)
Because of its amazing blue colouring, Lapis has been prized; carved and worn throughout antiquity, in pieces like this Roman Imperial Eagle. I saw quite a lot of it in precious pieces in museums while travelling in Egypt.
Lapis is believed to be good for communications and good judgement, for enhancing memory, and to attract success.
Lapis is gorgeous – and I have these pieces in my gemstone collection just waiting to be made into something fabulous!
Mookaite is a type of silicified porcelanite, which forms in silt-stone from the lower Cretaceous period that is found over much of the Carnarvon Basin in Western Australia.
(photo credit Michelle Pemberton)
The name Mookaite is derived from Mooka Creek, where the rock is mined. According to locals, the Aboriginal word “mooka” means “running waters”.
(photo credit Creative Crystals)
Mookaite is believed to be a healing stone that bestows strength. It is said to shield the wearer from difficult situations and to connect us to loved ones who have passed away. It is thought to assist with assessing problems and making decisions. Mookaite is used to treat glandular or stomach disorders, hernias, ruptures and water retention.
Mookaite comes in many lovely colourways. I have these pieces in my gemstone collection just waiting to be made into something fabulous!
Haematite is the mineral form of an iron oxide. It can be black to steel or silver-gray; brown to reddish brown; or red. It is mined as the main ore of iron.
BotryoidalHaematite (photo credit Harvard Museum of Natural History)
Gray hematite is typically found in places where there has been standing water or mineral hot springs. Haematite has also been discovered on Mars!
Haematite on Mars (photo credit NASA)
The name haematite is derived from the Greek word for blood ‘αἷμα haima’ as haematite can be red. It is used by jewellers in powdered form (with grease added) for fine polishing and is called rouge.
Red Haematite (Michigan)
Haematite is believed to have grounding properties. It is thought to help reduce the discomfort of leg cramps and broken bones. It is also thought to cleanse the blood, and help with blood-related diseases such as anaemia.
Haematite Sphere (photo credit Manchester Herbs)
There are some lovely haematite cabochons in my gemstone collection. If you’d like something beautiful made, let me know!
Labradorite is a type of feldspar consisting of between 30-50% Albite and 50-70% Anorthite. It was named after peninsula of Labrador in Canada, where it was first found.
Labradorite shows labradorescence – a schiller effect in lustrous metallic tints, often blue and green, and sometimes the complete spectrum. This effect is also found in moonstone.
Labradorite is believed to stimulate imagination, help develop enthusiasm and to see more clearly in meditation. it is thought to assist with disorders of the eyes and brain and to relieve anxiety.
It is supposed to balance hormones and relieve menstrual tension; and regulate metabolism. Labradorite is used to treat colds, gout, and rheumatism, lower blood pressure, and aid in digestion.
I have some gorgeous labradorite cabochons just waiting to be turned into beautiful jewellery for you – you can find them in my gemstone collection. Let me know what you’d like created!
When I first began setting gemstones, I was dismayed to be told that one that I had chosen might have been dyed. I felt a bit cheated. Surely every gemstone was just rock that came out of the earth? I did some research, and soon found that just about every precious gemstone you see has been treated in some way, and that some of the methods have been utilised for millenia – one of the first records of treating gemstones was written by Pliny the Elder (23-79AD), and methods he outlined are still in use today.
In truth, we alter almost every gem that comes from the earth, at least by cutting and polishing it. We also treat gems in ways that can change the colour or clarity of the stone. There are some gemstones that would not even exist if it were not for treatments. Not only are these treatments acceptable, they are necessary to keep these products affordable and available. There are varying degrees of enhancements – some are permanent and cannot be detected; others are obvious; and some are less stable and may diminish durability – these should be avoided if possible.
While the gemstones I use in my work are semi-precious, and therefore should not be price-affected by treatment (and have usually not to my knowledge been treated) some of them have been (including the majority of the drusy agates I use, which have been quite obviously dyed). If any treatment is not obvious but has been disclosed to me or is apparent to me when I buy the stones, I will note that in my listing for the stone or piece.
Bleaching
Bleached Coral (photo credit Tomomarusan)
Bleaching is a chemical process used to lighten either a component of or the entire color of a porous gem. Some gemstones are bleached and then dyed. Bleaching is permanent and undetectable. Bleaching is usually followed by polymer impregnation, as the process leaves materials vulnerable to breakage.
Gems that are commonly bleached include jadeite and pearls; some coral, ivory, and chalcedony may also be bleached.
Bleached gems tend to be more brittle, and they may be more porous and thereby absorbent of human oils and other liquids. Pearls should be kept in a soft, dry environment to avoid surface damage.
Bleaching is virtually impossible to detect in most cases.
Dyeing
Obviously dyed drusy agate
Dyeing is the practice of introducing colored dyes into porous or fractured gems to change their color. Fractures are sometimes purposely induced by heating the gem so that an otherwise non-porous material can more readily accept the dye.
Some dyeing, i.e. of chalcedony and of pearls is prevalent, permanent, and acceptable – it is not deceitful as these colors do not occur in nature. Dyeing of other materials i.e. of jade, lapis lazuli, turquoise, coral, rubies, emeralds and sapphire may be less acceptable – dyeing of these materials is usually performed to disguise inferior quality stones.
Gems that are commonly dyed include pearls, chalcedony, lapis lazuli, black onyx, pearls, jade, coral, and howlite – howlite is often dyed and passed off as turquoise. The process has also been used since ancient times for materials such as turquoise, quartz, emerald, and ruby. Agate is also commonly dyed – most of the drusy cabochons I work with have been obviously dyed – these colors don’t occur in nature! Sliced agate is often dyed as well.
When dye is applied to porous materials, the durability is dependent on the stability of the dye. In gems with larger fractures, the dye can sometimes leak out. Many dyes can be removed if the gem comes into contact with a solvent such as alcohol or acetone. Some dyes are unstable with exposure to sunlight and can fade over time.
A qualified gemologist can detect dyed gems in most cases.
Fracture or Cavity Filling, Including Oiling
Emeralds are commonly oiled (photo credit Mauro Cateb)
Fracture filling and oiling are the practice of filling surface-reaching fractures or cavities with glass, resin, wax or oil to conceal their visibility and to improve the apparent clarity, appearance, or stability of gem materials. The filling materials vary from being solids (glass) to liquids (oils), and in most cases, they are colorless. The use of synthetic resins with hardeners often applied to make the process more permanent, in particular, is not considered an acceptable treatment. Filling does not repair the inclusion, it just makes it less visible.
Gems that are commonly fracture-filled include: amber, diamond, ruby, emerald; alexandrite, varieties of chrysoberyl, and demantoid garnets; quartz, aquamarine, topaz, tourmaline and other transparent gems.
Glass filling tend to be harder and therefore more durable than resins, oils or waxes.
In most cases, filled gems can be recognized by a qualified gemologist using magnification.
Avoid exposure of these gems to heat, ultrasonic cleaning, and changes in air pressure or chemicals. Filled emeralds can also be damaged by exposure to hot water used for washing dishes.
Heat Treatment
Tanzanite is often heat treated (photo credit Wiener Edelstein Zentrum)
Heating is the exposure of gems to high temperatures for the purpose of altering their color and/or their clarity and brightness. It can cause a stone to lighten, darken, or change colour completely. Unheated stones can come with a 50%-100% price increase – this doesn’t mean that the untreated gem is more beautiful, as in most cases the heating enhances the gemstone; the higher price is because of the rarity of the stone being unheated. It is usually irreversible.
The most commonly heat-treated gems include amethyst, apatite, aquamarine, citrine (naturally occurring citrine is very rare – almost all citrine in the market is heated amethyst); diamond (diamonds can be subject to ‘high pressure high temperature’ treatments, as this can alter the atomic structure of some types of diamonds; the treatment involves heating the diamond to high temperatures under high confining pressures to remove or change its color); ruby, sapphire, tanzanite (tanzanite is often a brown colour when mined – most of the shades of violet and blue available are heat treated); topaz, tourmaline and zircon.
Heat treatments in all of the gemstones mentioned above are considered durable and permanent under normal handling conditions.
Heating is detectable only by trained observers in a laboratory setting. Unheated rubies and sapphires will contain microscopic rutile needles or tiny gas bubbles in pockets of liquid which are evidence that these stones have not been heated.
Submitting gemstones to intense heat may render them slightly more brittle than usual, and care must be taken not to damage pointed faceted corners and edges.
Impregnation and stabilization
Turquoise is often impregnated (photo credit Parent Géry)
Impregnation is the process whereby the surface of a porous gemstone is permeated with a polymer, wax or plastic to give it greater durability and improve its appearance. Stabilization is the introduction of a bonding agent, usually plastic, into a porous material. Of the two processes, stabilization is the most permanent. The upside to stabilization is that treated gems will not absorb oils and discolor as much as untreated ones. Some gems are waxed on the surface to enhance luster but this is not very usual. Opal can be stabilized with plastic to hide crazing, but this is not common and would only be done deceptively.
Most commonly encountered wax or plastic impregnated gemstones are opaque. The most commonly encountered dyed gems include turquoise, lapis lazuli, jadeite, nephrite, amazonite, rhodochrosite and serpentine.
Impregnations are often only surface deep, and due to the melting point of plastic and wax, can be susceptible to heat damage. Plastic impregnations are considered durable in gem materials such as turquoise as long as they are not subjected to heat or chemicals.
In most instances a qualified gemologist can identify this treatment.
Irradiation
Irradiated Topaz (photo credit Rob Lavinsky)
Irradiation is the exposure of a gem to an artificial source of radiation to change its color. (This is sometimes followed by a heat treatment to further modify the color).
Most irradiated gems will not contain any harmful residual radiation. There are some interesting articles about irradiation safety here. According to a scientist’s report I read, the only areas of potential danger are gemstones which have been irradiated by a neutron beam (which takes place inside a nuclear reactor), and given the short half life of the materials in gemstones, they should be harmless within a week of this treatment.
The most commonly irradiated gems include diamonds, corundum (includes ruby and sapphire), topaz, pearls, quartz, some varieties of beryl and spodumene.
The colour of some irradiated gems fades upon exposure to strong light. Blue topaz, diamond and quartz tend to have very stable colors as long as they are not exposed to high temperatures.
Because strong blue colors do not occur naturally in topaz, strong blue topaz stones can be considered to have received irradiation treatment. Strong colors in green, pink, and red diamonds should also be considered suspect. Determination of whether a colored diamond is natural color or treated color requires examination by an experienced gem-testing laboratory.
Laser Drilling
Diamonds are the only gemstone that are laser drilled (photo credit Rob Lavinsky)
This technique involves using a focused laser beam of light to burn an open channel from the surface of a diamond to reach dark inclusions in the stone. This is generally followed by vaporizing or bleaching to dissolve or alter the appearance of the inclusion. Diamonds are the only gemstones that can be treated in this fashion, in part because only they can withstand the heat of a laser.
While lasers could potentially affect the structure of a diamond, most laser drill holes are microscopic, and have no effect on the durability of the diamond.
Easily detectable by most gemologists and qualified gemological laboratories because of the presence of the laser drill holes. There are no special care requirements for laser-drilled diamonds.
Lattice Diffusion
Sapphires can be subject to Lattice Diffusion (photo credit Sapphiredge)
Lattice diffusion is the penetration of certain elements into the atomic lattice of a gemstone during heat treatment, with the objective of changing or accentuating its color. Diffusion was originally used on sapphires. Chemicals, like beryllium, were infused at high temperatures, and actually penetrated the gems. Early diffusion only produced color on the surface of the gem’s surface and was referred to as surface diffusion. Great advancements have been made in diffusion treatment and it was discovered that if corundum is heated to very high temperatures for a long duration, the diffusion would penetrate the entire stone. It can improve color, change color, or create asterism (stars).
The most commonly encountered diffused gems include: Corundum (ruby and sapphire), diamonds (if you look at a filled diamond closely and rotate it under light, you should be able to notice a bluish flash); feldspar (varieties of feldspar, notably andesine and labradorite are receptive to the diffusion of copper, completely altering their color); possibly tourmaline and tsavorite garnet.
The treatment is considered permanent. It is extremely difficult even for qualified laboratories to detect with certainty. There are no special care requirements for diffusion treated corundum or feldspar.
Surface Coating
Titanium Coated Drusy
Coating, a process which has been in use for over two hundred years, alters a gem’s appearance by applying a coloring agent (like paint, lacquer, or thin film) to the surfaces of gems.
The most commonly encountered coated gems include: diamonds, tanzanite, topaz, coral, pearls, quartz (some of the drusy cabochons I use have been coated with titanium); and opals.
Because they tend to be softer than or may not adhere well to the underlying gem, thin-film surface coatings of any kind are susceptible to scratching, particularly along facet edges and junctions. Care should be taken to not allow any hard or abrasive objects to come in contact with coated gems.
The treatment is easy to identify by a skilled gemologist except where the coating substance is colorless and it has been added to improve durability.
When they are not being worn, coated gem materials should be wrapped in soft packaging and kept in a dry environment.
Gemstones That Are Not Enhanced
Malachite is not known to be enhanced
There are some gemstones that are not known to be enhanced. These include:
garnet (with the exception of demantoid)
peridot
iolite
spinel
varieties of chrysoberyl
tourmaline (with the exception of the Paraiba variety)
malachite
hematite
feldspar (with the probable exception of varieties of andesine and labradorite).
Bear in mind that new technology in gemstone treatment is always changing and improving and many techniques are difficult, if not impossible, to detect.
Disclosure
Here in Australia, the ACCC states that consumers should be able to “have a reasonable expectation that any treatment of gemstones to enhance their aesthetic appearance and value would be disclosed where the treatment is either not permanent or creates special care requirements, such as through the application of colourless oils, or the previous
practice of fracture filling. Additionally, businesses which fail to disclose gemstone treatments, where the value of treated gemstones is significantly less than the value of an equivalent untreated gemstone, may also risk contravening the misleading and deceptive conduct provisions of the Act.”
A gemstone vendor should always disclose any known treatments or enhancements; however, remember they may not always know themselves, especially with imported gems. Most gemstone vendors are honest and will let you know, but it is your responsibility to ask.
All in all, one of the reasons I enjoy working with semi-precious rather than precious stones is that they are less ‘valuable’ in monetary terms, and more likely to have come out of the ground the way they are – conversely though, to my mind, as long as the stone is obviously enhanced and you’re not being fooled into paying more for it, why not have fun and enjoy it! So, tell me – what do you think about treated gemstones?
According to Wikipedia, Chrysocolla is a hydrated copper cyclosilicate mineral with the formula (Cu,Al)2H2Si2O5(OH)4·nH2O. Hehehe, such a convoluted scientific string! I guess that just means it’s a compound, which is apparent from the many wonderful blue/green colourways that can be seen in various pieces.
Chrysocolla (photo credit Great Rough)
Chrysocolla is a minor ore of copper, and like malachite, has a high copper content, which is what gives it that fabulous blue/green colouring.
Chrysocolla – Botryoidal (photo credit MinDat)
The name Chrysocolla derives from the Greek chrysos (gold) and kolla (glue), referring to its use as a flux in soldering gold. The term has been used since antiquity.
Chrysocolla Stalagtite (photo credit MinDat)
It is believed to have a calming influence, and also to attract love. It is supposed to help heal burns, fever, and detoxify the liver.
Chrysocolla (photo credit Mineral Miners)
I have some lovely chrysocolla cabochons just waiting to be turned into beautiful jewellery for you – you can find them in my gemstone collection. Let me know what you’d like created!
Puddingstone is the popular name for an agate conglomerate, so called because of the plum pudding-like appearance of the rounded pebbles whose colours contrast with the matrix which surrounds them.
Puddingstone Slice (photo credit East Herts Geology Club)
There are different types of puddingstone, with different composition, origin, and geographical distribution. Examples of different types of puddingstones include the Hertfordshire, Schunemunk, Roxbury and St. Joseph Island puddingstones.
Remains of a stone circle of pudding stone incorporated into the structure of St Mary’s Church, Chesham, Buckinghamshire (Photo credit Iridescent)
Puddingstone has been used since at least Roman times as a building material, and also for grinding corn shaped into a device called a quern.
Puddingstone Quern (Photo credit St Albans Museums)
Puddingstone is believed to be useful in assisting with anxiety or stress.
Large Puddingstone (photo credit DI Showshoe)
Puddingstone is used to prevent tissue deterioration of internal organs and muscles, to strengthen immune system and to promote body balance. It is supposed to help alleviate any pain or disorder.
Puddinstone Sphere (Phot0 credit The Rock Shed)
This gorgeous Puddingstone cabochon at the top of this post, which comes from Agate Creek right here in Queensland, Australia, was snapped up by a lovely client of mine. I made this ring for her.
Contact me if you’d like me to create a custom piece for you!
Rhyolite is a volcanic rock, and is known as the volcanic equivalent of granite. It is sometimes known as Rainforest Jasper. Its occurrence is quite widespread throughout the world.
Flow-banded Rhyolite (photo credit Angela Walker)
Pre-historic quarries of rhyolite have been discovered in the location of east Pennsylvania, USA. Rhyolite was given its name by the German traveller and geologist Ferdinand von Richthofen after his explorations in the Rocky Mountains in the 1860s.
Rhyolite – Slab (photo credit GemrockAuctions)
Rhyolite is supposed to spark creativity in individuals who are ready to move forward and make things happen in their life. It apparently helps to break through the mental barriers.
Rhyolite – Polished Stone (photo credit GreenEarthStones)
This stone is used for meditation, progression in life, focusing on the present moment and resolving issues not yet complete.
Rhyolite – Sphere (photo credit Crystalarium)
I had the lovely piece of rhyolite in cab form shown at the top of this post,which I made into a pendant. If you’d like a pendant of your own, just contact me and let me know!