Facts and figures about Gem Stones.
What are Stones & Crystals?
All solids tend to form crystals - even metals when examined under the microscope are crystalline. To prevent crystals forming the molten material must be cooled quickly - as is glass. Almost all gems are crystalline, except opal.
In crystals the atoms are arranged in order, and as a result most single crystals are transparent to light. The light will be refracted internally, often split into 2 rays, and show the same rainbow effects as if passed through a prism. While some minerals are always coloured, quite often it is impurities within the crystal which cause the different colours - somehow impurity seems the wrong word to describe what causes the beautiful colour of gemstones! These impurities are traces of other elements, which don't form part of the basic crystal structure.
Some gemstones consist of many
small crystals, which do block the light and appear opaque
However when I came to prepare this list I encountered a problem. Every reference work gives a different list! One major difficulty is that some stones are both linked to months and a relating sign of the Zodiac, so can be applied to either of the months linked to that Zodiac sign.
In the end I had to put together the different lists and wrote my own, after consulting various lists from several continents written over a period of many years. I have tried to avoid artificial stones, and if I have listed them have made it clear that they are man-made. In most cases at least the stones in the various lists look similar - except March. Here Aquamarine is the first choice - a light blue-green, but some lists show Bloodstone, a very dark green with red flecks, so I decided to list both (but I have to say I prefer Aquamarine). So although my list may not be exactly the same as others, I have consulted many different sources and believe that it does represent a fair compromise.
Diamonds (April's Birthstone):
Diamonds come to life when they catch the light - then you will see all the colours of the rainbow sparkling from the stone. Diamonds are the hardest substance known to man and so rightly take the first place in this listing - strange to think they are made from the same material as pencil 'lead!' While we think all diamonds are colourless, a careful examination will show they come in a range of shades, varying from blue white towards brown. The brightest command the highest price. Also coloured stones do occur, and if attractive command a high price. Most diamonds are too flawed to be worn as jewellery, but are very useful in industry, their hardness making them excellent for drills, saws and polishing other stone.
They are so hard they can only be
cut or polished by another diamond. This only works because
diamonds are harder at some angles than others - a result of
the crystal structure. Before cutting a stone the cutter will
ensure that no facets will lie along this line of maximum
hardness - because these would be impossible to cut or polish.
Provided that particular angle is avoided some of the diamond
dust used in cutting and polishing will be harder than the
diamond which is being worked on.
The Corundum Minerals (Sapphire Is September's Birthstone, Ruby Is July's Birthstone):
Corundum is an aluminium oxide (AL2O3); apart from diamonds, this is the hardest mineral known to man. In industry corundum is used for abrasive materials including Emery. Although very hard, like other gems the stones are somewhat brittle, and can be cracked by a violent blow. They are easily cleaned with any proprietary cleaner or detergent.
While the blue form (Sapphire) is the most common, other colours do occur (The red form is Ruby), the best stones are a bright transparent colour.
The ancients believed high quality rubies protected the wearer from danger - but the effect would be lost if these stones mixed with lower quality rubies!
Most crystals contain inclusions
which reduce the stones' clarity, so good clean stones are
highly prized (although sometimes crystalline impurities can
be interesting in themselves).
Owing to their inclusions and
flaws, emeralds should not be soaked when cleaning. Also
always remember that although hard these stone - like other
gemstones - are somewhat brittle and can be damaged by a
Emeralds are the bright green form
of beryl - aquamarine is the light blue-green variety. Clear
deeply coloured emeralds are rare, most have inclusions, which
make them look rather milky.
Aquamarine means 'Water of the
Sea,' and the stone is a pale blue-green colour. While clear
emerald gems are very rare, aquamarine is often found totally
unflawed. It is a beautiful, light-coloured stone.
In ancient times it was used as a protection against drowning and sea-sickness, and was thought to bring good luck to fishermen.
(Blue Topaz Is Alternative March Birthstone, Golden Topaz Is
Alternative November Birthstone):
Unusually for the listed
alternative, Golden Topaz is actually the less common stone.
Topaz normally has a better colour than Citrine (the first
choice of November birthstone) as well as being harder.
While limited quantities of
natural Blue Topaz can be found, most of the stones available
at present are produced by irradiating and then heating
Like other gems, do remember that although hard it is somewhat brittle, and can be damaged by a violent blow from a hard object. It's easily cleaned with any detergent - make sure the back is kept clean, that's always important with transparent stones!
Peridot (August's birthstone):
Peridot is a silicate of magnesium and iron. It varies in colour from bright green through yellow-green, sometimes called Chrysolite. The colour is most attractive, and the stone has an oily sheen. It gets its colour from iron impurities.
It symbolises luck and success, the Ancients believed it dispelled fear of the dark and was an amulet against all evil.
Caring for Peridot; The gem can be safely soaked in lukewarm water, but should not be soaked in Silver Dip. It can be cleaned with any jewellery cleaner or detergent. This stone is softer than the precious stones, and can be scratched by sand etc. So don't wear it when gardening or doing other rough work!
Garnet - January birthstone.
Everybody knows garnets are red, in fact other colours can be found - but not blue. From ancient times garnets have been valued as keeping the wearer safe from harm, and were especially prized by warriors both to protect them from injury, and to give them a feeling of peace and tranquillity. Curiously, they were also believed capable of inflicting fatal wounds, and in 19th Century Kashmir garnets were used as bullets for attacking British troops. The ancients believed the wearer would be blessed with good health, and the stone would ward off nightmares.
Chemically these are compound silicates, and come in a number of different formulae. The better stones look great when faceted, while others are given a cabochon finish.
Cleaning won't pose any problems, the stones can be safely soaked in warm water, then cleaned with detergent. However do note these stones are only as hard as silica, which is a main constituent of sand, soil and also household dust. So avoid wearing garnet rings when working.
Quartz (Amethyst Is February's Birthstone, Rock Crystal Is The Alternative April Birthstone):
Varieties of Quartz include: Agate, Amethyst, Aventurine, Carnelian, Chalcedony, Citrine, Jasper, Milk Quartz, Onyx, Prasiolite, Rose Quartz, Rock Crystal, Rutilated Quartz, Smoky Quartz and Tiger's Eye.
Composed of silicon dioxide, quartz is very common, although gem quality is less so. In its pure form it is colourless, and the colours are caused by impurities - often trace amounts of metals.
Rock Crystal is colourless quartz, and was believed by the ancient Greeks to be fossilised ice.
Amethyst is the symbol of sincerity. This beautiful variety of quartz comes in many shades, from palest lilac to deep purple. The Egyptians placed amethysts on the body of the deceased. It was believed to prevent drunkenness (the name comes from the Greek Amethystos, meaning non-intoxicating). It was supposed to protect against spells, and bestow business success and intelligence.
Quartz is easy to clean, you can safely soak it in water, and clean the stones with detergent. I have found these stones do benefit more than most from frequent cleaning. The transformation when a stone is cleaned can be amazing! Do remember that quartz is the main constituent of sand, soil and also a part of household dust. So all these things can scratch the stones. Avoid wearing these rings when doing rough work - anyway rough work would also scratch gold and silver.
This stone comes in a range of shades, varying from pale yellow through orange. It symbolised generosity, and was thought to safeguard secrets and was considered a stone of mystery and subtlety.
These stones are all varieties of Chalcedony - which is composed of many small quartz crystals, so they are translucent.
These stones will take up dyes in time, although staining is most unlikely under normal conditions.
An attractive banded stone, normally forms in geodes - hollows in rocks - when super-heated water rich in silica deposited the silica in the hollows.
When sliced its translucency and colour patterns are seen to advantage.
Bloodstone - alternative March Birthstone.
Some listings give Bloodstone as the stone for March while others list Aquamarine. Bloodstone is a dark green chalcedony with speckles of red jasper. These days it is rather uncommon, although sometimes seen in signet rings.
Hardly surprising in view of its name was the ancient belief that it stopped bleeding! Even more intriguing is the thought that when correctly used with the herb Heliotrope the wearer becomes invisible.
Carnelian - Alternative July birthstone.
This is a red-brown stone, and was much used in ancient times for carving seals.
Green Agate - Alternative May birthstone.
This is dyed chalcedony, and is translucent, it is a useful alternative for emerald, especially if a larger stone is required
Malachite - Alternative May birthstone.
Composed of copper carbonate, a major ore of copper, Malachite is rather soft for jewellery; however its softness does mean that it can be carved into beautiful forms. It is opaque, with attractive banding. When made into jewellery the owner should realise that it will be easily scratched by soil or dust. However its colour and banding does make it very attractive. When cleaning, it should not be soaked.
Moonstone - Alternative June birthstone.
Moonstones are one of the feldspars - a group of aluminium silicates, which is the most common group of minerals within the earth's crust. Despite its common nature, Moonstone is the only representative of the feldspars in this list. There are several other gemstones in the series, but you are probably most familiar with feldspar after it has been decomposed into kaolin.
Actually there are two different moonstones, very similar in appearance and both are varieties of feldspar.
They are normally colourless and somewhat translucent and appear to have a soft 'mobile' reflection within the stone; move the stone and the location of the reflection will appear to move. See the stone, and you'll realise what I mean, it really is hard to describe in words. They certainly do have a most fascinating appearance.
Moonstones were associated with the Moon goddess Luna, and
symbolise modesty and purity.
Lapis Lazuli - Alternative September birthstone.
Lapis Lazuli is a deep blue opaque stone, when crushed it forms the pigment Ultramarine. Its chemical composition is complex and includes varying amounts of lazurite, calcite, pyrite and feldspars along with other stones. It should not be soaked when being cleaned. It is also rather softer than most of the gemstones in this list, so should not be worn when doing heavy work.
It was a popular stone for carving in antiquity.
Opal - October birthstone.
Each stone is different, and as it is moved, glimpses of rich
colours appear within it. The colour is produced by an
interference effect within the stone's structure, similar to
the rainbow effects produced by a thin film of oil on water.
The best stones show their colour against a black background,
but many are a milky white with the colours glowing within
that mist. Opal is made from silica, but it is not
crystalline, rather it consists of many minute 'balls' of
silica arranged in a regular fashion, and so minute that they
cause interference patterns in the light they reflect.
However in Classical times the opal was highly regarded. Mark Anthony outlawed a senator who refused to yield his opal! The stone was believed to bring good fortune, and warn of poison. Along with many other stones, it was considered a protection against disease.
Along with many other semi-precious stones, opals can be scratched if worn (especially in rings) when doing rough work - and a badly scratched opal will lose much of its fire. The stones are slightly porous, so should not be soaked in anything. Note opal doublets are manufactured - opals backed or capped by another stone. These should be treated very carefully.
Turquoise - December birthstone.
An opaque blue stone, sometimes blue-green or green; the blue colour is the most highly prized. Chemically it is a hydrated phosphate of copper and aluminium. It was one of the first stones to be mined - by the Egyptians over 6000 years ago. The Turks, after whom it is named, introduced it into Europe. Much turquoise on the market today has been 'enhanced,' either by treating with paraffin wax or resin
It was believed to protect the wearer from injury, and Turkish horsemen in particular used to attach the stones to the horses' harness. Some people believed the stone changed colour, either becoming white when the owner died, or its colour forecasting the weather.
Caring for Turquoise
The owner should remember this stone is porous, and can easily absorb grease, and other substances. Take it off when washing up, and keep it away from things like hair-spray. When cleaning do not soak it. It is also rather soft, and should not be worn when doing any rough work.
Pearls - June birthstone
These pale gems have an attractive soft sheen - different from many other stones. They come in a range of muted shades, and their sheen makes them very pleasing to the eye. Most are spherical - and these are more highly prized, however odd shapes, called baroque, also occur especially with freshwater pearls.
Natural pearls are rare and very expensive, most pearls are cultured deliberately by inserting an irritant in an oyster. There are many synthetic pearls on the market, of varying quality. At the time of writing, cultured freshwater pearls represent very good value for money, although it is not known if the present low price will last indefinitely.
They are rather soft, so don't wear them when doing rough work. They should not be soaked in anything. Some authorities say the best way to clean pearls is to wear them, otherwise restore their sheen by polishing gently on soft chamois leather.
Cleopatra believed that drinking pearls dissolved in wine enhanced her legendary beauty. In antiquity they were associated with the Moon Goddess, Luna.
Cubic Zirconia - Alternative April birthstone.
C.Z. is a man-made substitute for diamond - very close to diamond in appearance, but not as hard. Like diamonds they come to life when they catch the light, and you will see all the colours of the rainbow sparkling in the facets. While most people only know the colourless simulant for diamond, the stone is also made in a wide range of colours.
Although the stone is often considered a cheap substitute for
diamond, I consider it is best regarded as an attractive stone
in its own right. Pretending that your ring contains a
valuable diamond when it clearly is only an imitation won't
enhance your image. So wear C.Z. because it is attractive, it
sparkles and it looks good in its own right.
If you look at a stone through a lens, you will see the image of the back of the stone is doubled. This effect does occur with many stones, but is most easily seen with zircon.
C.Z. is hard enough to stand up to normal wear, it is about as
hard as emerald. You can soak it without damaging it. However
I always find it benefits from frequent cleaning, especially
the back of the stone - if that gets dull it really does spoil
the appearance. You can clean it with any detergent, brushing
with an old toothbrush.
Imagine the sun's rays - petrified. That's what the Greeks
believed amber to be.
Sometimes it contains air-bubbles; scientists can analyse them
to learn about earth's ancient atmosphere.
Why is amber so great for jewellery?
Unlike gemstones, amber is warm to the touch. It's also lighter than stone, so it's possible to make large spectacular pieces of jewellery, items which would be too heavy if made with any other material.
Much of the amber you will see in European shops has come from Eastern Europe. Skilled silversmiths (often in Poland) enhance its beauty with elegant silver mounts. Because the exchange rate works in our favour, these pieces can be purchased at very competitive prices, especially when you consider how much work goes into producing them. Buy now, and you'll be the proud owner of a beautiful piece of jewellery.
Amber comes in a range of colours. So if you want to wear several pieces of amber jewellery together, make sure their colours complement each other.
Some amber is cloudy (this is often minute air bubbles), sometimes you may see inclusions, bits of petrified plant debris, and if you are really lucky you may even find a preserved insect. It is for you to judge how these different qualities affect the value and beauty of a piece.
Amber can be quality enhanced. By careful heating it is possible to clarify cloudy amber; often "Sun spangles" will be included in such enhanced amber. There is no attempt to deceive here, as this effect does not occur naturally, rather it is an attempt to upgrade the appearance of the amber.
When other stones are 'enhanced' the basic nature of the stone is not changed, the defects are merely hidden, and in time may once again become apparent. However the enhancement of amber is different, the material is actually softened and the air bubbles and inclusions removed before the stone resets, therefore the amber is permanently altered, and will not deteriorate.
Finally it is the buyer's choice whether he wants to purchase enhanced amber. But in my opinion the clear amber that results from this work is beautiful, and well worth owning. On the other hand if you prefer amber in its natural state there are many attractive pieces to be found.
At present, amber is easily available and is great value. Now is the time to buy.
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