GEMSTONES

What is a gemstone?

Gemstones are primarily mineral crystals that can be cut and polished for use in jewellery. Examples include diamonds, emeralds, sapphires, rubies, and tourmalines. Some organic materials like amber, pearls, and jet are also considered gemstones. Gemstones are chosen for their beauty, rarity, and durability.

Gemstone Classification: The traditional distinction between precious and semi-precious gemstones has largely been abandoned. However, some gemstones like emeralds, rubies, and sapphires still command higher prices. For significant purchases of these stones, obtaining a gemstone identification report from a reputable laboratory is advisable.

When shopping for coloured gemstones, it’s essential to choose a reputable Jewellers Association of Australia Member. This ensures that you receive the highest quality gemstones along with transparency in your purchase.

GEMSTONE TREATMENTS

Many gemstones undergo treatments to enhance their appearance and value:
Heat Treatment: This is the most common treatment, especially for rubies and sapphires. It's used to improve colour intensity and clarity.
Diffusion Treatment: Often combined with heat treatment, diffusion involves adding elements like beryllium or titanium to enhance colour.
Irradiation: Used to alter gemstone colour, particularly in topaz, tourmaline, and fancy diamonds. This is typically followed by heating.
Clarity Enhancement: Surface-reaching fractures or fissures are filled with glass, resin, or oil to improve transparency and durability.
Coating: A thin film is applied to the gemstone's surface to modify colour, lustre, or brilliance.

When buying treated gemstones, it's important to note that some treatments may affect the stone's durability or care requirements. Reputable sellers should disclose any treatments applied to gemstones.

ametrine

Colour
Purple and yellow 

Cut
Many faceted shapes and cabochons

Durability
Fairly durable 7.0 on Mohs scale

Origin
Only one commercial source in Bolivia

Treatments
Ametrine is not typically treated or enhanced

Laboratory-created
Can be manufactured in a laboratory

AQUAMARINE

Colour
Blue to green-blue

Cut
Many different shapes and sizes, cabochons, beads, carvings

Durability
Fairly durable 7.5-8.0 on Mohs scale

Origin
Mainly Brazil. Afghanistan, Burma,
China, Kenya, Madagascar,
Mozambique, Ukraine, USA

Treatments
Almost always heat-treated to lessen subtle yellow colours

Laboratory-created
Can be manufactured in a laboratory but mostly imitated by other blue stones

CARNELIAN

Colour
Light Orange to deep Reddish brown

Cut
Smooth Cut, Beads or Cabochons

Durability
Fairly Durable 6.5 to 7.0 on Mohs Scale

Origin
Various locations worldwide, Brazil,
India, Madagascar, Uruguay, USA

Treatments
Some may undergo heat treatment

Laboratory-created
Can be manufactured in a laboratory

Chyrysoprase

Colour
Apple green variety of chalcedony

Cut
Cabochons, Beads or carvings

Durability
6.5 to 7.0 on mohs scale

Origin
Australia, Brazil, Kazakhstan, Myanmar, Poland, Russia, Tanzania, USA

Treatment
Dyeing

Laboratory-created
Can be Manufactured in a laboratory

Citrine

Colour
Yellow to deep reddish-orange

Cut
Many different shapes and sizes, cabochons, beads, carvings

Durability
7.0 on Mohs scale

Origin
Mainly Brazil and Bolivia. Namibia, Madagascar and Zambia.

Treatments
Most citrines are heat-treated amethysts that turn yellow to reddish orange. Treatment is generally stable.

Laboratory-created
Can be manufactured in a laboratory.

Coral

Colour
Various colours ranging whites, reds,
and pinks to black, brown and gold

Cut
Usually bead or cabochon

Durability
3.0 to 4.0 on Mohs scale

Origin
The Mediterranean and Red Sea areas, most gem quality. Other notable produces include Hawaii, Australia, Cameroon, Taiwan, Japan, Malaysia, Mauritius, Spain, South Africa

Treatments
Dyeing and bleaching

Laboratory-created
Can be manufactured in a laboratory

Diamond

Colour
Many different colours. Mostly white to yellow but can come in fancy red, pinks, blues browns and greens
Cut
Many different faceted cuts

Durability
10.0 on Mohs scale

Origin
South Africa, Botswana, Russia, Australia, Canada

Treatments
Many treatments. Laser Drilling, Fracture Filling, Annealing, Irradiation, High Pressure/High Temperature and coatings

Laboratory-created
Can be manufactured in a laboratory.

Emerald

Colour
Deep greens to green-blue hues.

Cut
Can be cut into many shapes but mostly an "emerald cut', a rectangular set cut

Durability
7.5-8.0 on Mohs scale

Origin
Mainly Colombia. Afghanistan, Brasil, Canada, China, Egypt, Madagascar, Russia, USA, Zambia, Zimbabwe

Treatments
Often have fractures, which are treated with oils, resins, or polymers to improve colour and transparency

Laboratory-created
Can be manufactured in a laboratory

Garnet

Colour
Mostly red but come in a rainbow of colours - greens, oranges, pinkish oranges,  deeply saturated purplish red

Cut
Can be faceted, cabochons or beads

Durability
6.5-7.5 on Mohs scale

Origin
Brazil, Germany (spessartine), Kenya (tsavorite), Madagascar, Sri Lanka, Russia (demantoid), Tanzania, USA

Treatments
Rarely treated, as there is little need to enhance their colour or clarity

Laboratory-created
Can be manufactured in a laboratory

Hematite

Colour
Black to steel or silver grey,  brown to reddish brown with a metallic lustre

Cut
Often polished, beaded or carved and rarely faceted

Durability
5.0 to 6.5 on Mohs scale

Origin
England, Brazil, USA, Canada, Cuba,
Elba, Italy, Mexico

Treatments
Not usually treated

Laboratory-created
Can be manufactured in a laboratory

Iolite

Colour
Violet to blue

Cut
Can be cut into many shapes

Durability
7.0 to 7.5 on Mohs scale

Origin
Most of the worlds Iolite comes from India, but substantial amounts are also mined in Tanzania, Brazil and Sri Lanka

Treatments
Rarely treated. Can't be heat treated

Laboratory-created
Can be manufactured in a laboratory

Jade

Colour
Predominantly green but can also come in lavender, yellow, red, white and black

Cut
Cabochons, Beads, Bangles and carvings

Durability
Durable 6.5 to 7.5 on Moh's Scale

Origin
Burma is the primary source of high-quality jadeite, Russia, Guatemala, Japan, Kazakhstan, California and Mexico also have some jadeite deposits

Treatments
Heat Treatments, Coatings, Dyeing, Bleach and Polymer treatment

laboratory-created
Can be grown in a laboratory

Jasper

Colour
Jasper can be found in many colours but do tend to be earthy tones. Red, Brown, Orange, Yellow and green and tend to have two or more colours in each stone

Cut
Nearly always cut into rounded shaped or cabochons then polished

Durability
Durable 6.5 to 7.0 on Moh's scale

Origin
Common mineral that can be found all over the world. Australia and Brazil are major producers but can also be found in India, Madagascar, South Africa, United States, Russia and Mexico

Treatments
Not usually treated

Laboratory-created
Inexpensive material usually not laboratory grown

Kunzite

Colour
Ranges from delicate pastel pink to intense violetish purple

Cut
Fancy faceted shapes and cuts

Durability
Durable 6.5 to 7.0 on Moh's scale

Origin
Found in Afghanistan, Brazil,
Madagascar and California

Treatments
Can be heat treated and irradiated. Both treated and natural colour in Kunzite can fade if exposed to heat and bright light

Laboratory-created
Can be grown in a laboratory

Labradorite

Colour
Predominantly blue or gold, green, orange, pink, yellow, colourless, with grey, grey- white and brown body colour

Cut
Usually cut into cabochons to maximise sheen (labradorescence)

Durability
Durable 6.0 to 6.5 on Moh's Scale

Origin
Labrador Canada is the primary source but has also notable finds in
Madagascar, Finland, Russia, Australia
and The United States

Treatments
Heat treatments and diffusion. There are no known treatments for labradorite that show labradorescence

Laboratory-created
Can be grown in a laboratory

Lapis Lazuli

Colour
Deep Blue with gold coloured (pyrite) inclusions

Cut
Typically cut into cabochons, beads, inlays or tablets. Can also be carved, boxes, mosaics, ornaments, Small statues and vases

Durability
Relatively soft. 5.5 on Moh's scale

Origin
Afghanistan, Russia, Chile, Myanmar, Pakistan, Argentina and The United States

Treatments
Commonly dyed with a coating of wax or plastic to seal in the dye

Laboratory-created
Can be grown in a laboratory

Malachite

Colour
Green with varying banded patterns

Cut
Mostly cabochons, beads and can be carved into cameos.

Durability
3.5 to 4.0 on Moh's scale

Origin
Zaire, Australia, Chile, Namibia, Zimbabwe and Arizona

Treatment
Sometimes coated with wax or resin to increase hardness

Laboratory-created
Can be manufactured and a laboratory

Moonstone

Colour
Occurs in a number of body colours, White, Grey, Brown, Pink and orange. Adularescence is usually a white to slivery sheen and sometimes (rarely) a blue colour in colourless specimens

Cut
Mainly cabochons or beads

Durability
6.0-6.5 on Mohs scale

Origin
Armenia, Australia, Austrian Alps, Mexico, Madagascar, Myanmar, Norway, Poland, India, Sri Lanka and The United States

Treatments
Usually not treated. Some specimens may have a coating to enhance adularescence

Laboratory-created
Cannot be manufactured in a laboratory

MoRGANITE

Colour
Pink to Orangey-Pink

Cut
Many different faceted and carved
shapes and sizes

Durability
Durable 7.5 to 8.0 on Moh's Scale

Origin
Brazil, Afghanistan, Mozambique,
Namibia and The United States

Treatments
Almost all Morganite is heat treated
to enhance colour

Laboratory-created
Can be manufactured in a laboratory

Onyx

Colour
Most commonly black, can be banded, brown, green red and white

Cut
Mainly cabochons or beads

Durability
6.5 to 7.0 on Mohs scale

Origin
Mexico, Argentina, The United States, Brazil, India, Madagascar,  and Uruguay

Treatments
Can be treated or dyed

Laboratory-created
Can be manufactured in a laboratory

Opal

Colour
Can have a fiery play-of-colour but can also be colourless, opaque, translucent or transparent

Cut
Mainly cabochons or beads

Durability
5.0-6.5 on Mohs scale

Origin
Mostly Australia, where it is our national stone. Brazil, Ethiopia, Madagascar, Meixco, Peru

Treatments
Treated to enhance their colour or appearance

Laboratory-created
Can be manufactured in a laboratory

Pearl

Colour
Can have a fiery play-of-colour but can also be colourless, opaque, translucent or transparent

Cut
Mainly cabochons or beads

Durability
5.0-6.5 on Mohs scale

Origin
Mostly Australia, where it is our national stone. Brazil, Ethiopia, Madagascar, Meixco, Peru

Treatments
Treated to enhance their colour or appearance

Laboratory-created
Can be manufactured in a laboratory

Pearl - Mother of Pearl

Colour
Usually white, to iridescent shades of pink, blue and green

Cut
Usually free form shapes, inlay or carvings

Durability
2.5 to 4.0 on Moh's scale but its compact structure enhances its strength and resistance to impact and wear

Origin
Found in many locations worldwide. Significant producers include Australia, Japan, China, The Philippines and Thailand

Treatments
Dyeing, Bleaching and polishing

Laboratory-created
Can be manufactured in a laboratory

Peridot

Colour
Yellowish green to greenish yellow to brownish-green

Cut
Many different shapes and sizes,
carvings and beads

Durability
6.5-7.0 on Mohs scale

Origin
Burma, China, Pakistan, USA have the most productive sources.  Australia, Brazil, Ethiopia, Kenya, Norway and Sri Lanka are sources too

Treatments
Rarely treated

Laboratory-created
Cannot be manufactured in a laboratory

Quartz

Colour
Colourless, Pink, Brown, Yellow,  Orange, green, blue, black and purple

Cut
Many different faceted and cabochon shapes

Durability
7.0 on Mohs scale

Origin

Found in many locations worldwide. Significant producers include Brazil, China, Turkey, Spain India and The United States

Treatments

Can be irradiated and heat treated

Laboratory-created
Can be manufactured in a laboratory

RHODOLITE

Part of the garnet family

Colour
Reddish-purple

Cut
Round, pear, oval, cushion, emerald cuts

Durability
7.0-7.5 on Mohs scale

Origin
Afghanistan, Cambodia, India, Madagascar, Pakistan, Sri Lanka, Tanzania, Vietnam. Burma is known to produce the finest quality rubies.

Treatments
Treated to increase transparency, clarity and colour. Use of lead glass to fill pits and cracks or oils and dyes may also be used, but these treatments are not considered durable

Laboratory-created
Can be manufactured in a laboratory

RUBY

Colour
Finest rubies are pure, vibrant red to slightly purplish red. Can be found in various shades of red, tone of oranges, brown or pink

Cut
Round, pear, oval, cushion, emerald cuts

Durability
9.0 on Mohs scale

Origin
Afghanistan, Cambodia, India, Madagascar, Pakistan, Sri Lanka, Tanzania, Vietnam. Burma is known to produce the finest quality rubies.

Treatments
Treated to increase transparency, clarity and colour. Use of lead glass to fill pits and cracks or oils and dyes may also be used, but these treatments are not considered durable

Laboratory-created
Can be manufactured in a laboratory

Sapphire

Colour
Sapphires come in all colours of the rainbow including yellow, green, orange, pink, purple and blue. Best described by their colour, such as "yellow sapphire". Deep blue is the most prized

Cut
Sapphires come in all shapes, with star and cat’s-eye varieties cut as cabochons. Some change colour in different light, making them prized collector's gems.

Durability
9.0 on Mohs scale

Origin
Australia, Burma, Cambodia, China, India, Kenya, Laos, Madagascar, Nigeria, Sri Lanka, Tanzania, Thailand, USA, Vietnam

Treatments
Often heat treated to improve both clarity and colour

Laboratory-created
Can be manufactured in a laboratory

SPINEL

Colour
Range from orange to intense red or pink, and all shades between purple, blue and violet to bluish green. Most valued are bright red, cobalt blue and vivid pink and orange, while pale lavender spinels are the more affordable option

Cut
Faceted into many shapes and sizes,
most often cushion and oval shapes

Durability
8.0 on Mohs scale

Origin
Afghanistan, Brazil, Burma, Cambodia, Kenya, Russia, Sri Lanka, Tanzania, Thailand, Vietnam

Treatments
Generally not treated

Laboratory-created
Can be manufactured in a laboratory

Tanzanite

Colour
Lush blues, vibrant violets, rich purples

Cut
Many different shapes, carvings

Durability
6.0-7.0 on Mohs scale

Origin
Tanzania near Mt Kilimanjaro

Treatments
Most heat treated, causing change of colour in rough material from brown, purple or grey to shades of blue/violet

Laboratory-created
Cannot be manufactured in a laboratory

Tiger's Eye

Colour
Mainly brown and yellow.
Can be dyed any colour -
blue, green, red, purple or orange

Cut
Beads and large cabochons

Durability
7.0 on Mohs scale

Origin
Australia, Burma, India, Namibia,
South Africa, USA

Treatments
Can be heat treated or artificially lightened to improve colour

Laboratory-created
Cannot be manufactured in a laboratory