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Precious Stones

Information about cut and colour of precious stones.

A precious stone is a valuable stone, such as a diamond or a ruby,
that is used, among others, for making jewelry.
Let's start with an overview of different cuts

When a gemstone is desired to be used in jewelry, it is cut depending on the size and shape of the rough stone, as well as the desired piece of jewelry to be made. As a general rule, a cut gemstone will reduce the mass (described in the carat) by about 50 percent. A diamond’s cut refers to how well-proportioned the dimensions of a diamond are, and how these surfaces, or facets, are positioned to create sparkle and brilliance.

Precious stones come in a variety of colours

The most common gemstone colors are white, blue, yellow, orange, and red. Some of the rarer colors include green, pink, purple, and brown.
Here we have a selection of some interesting examples.

BLUE

Blue diamond

Very rare

SAPPHIRE

AQUAMARINE

RED

Red diamond

Very very rare

Ruby

PINK SAPPHIRE

RUBILITE TOURMALINE

GREEN

Green diamond

Very rare

EMERALD

TOURMALINE GROUP

AVENTURINE

DIOPSIDE

DIOPTASE

BERYL GREEN

PERIDOT

JADE-JADEITE

JADE-NEPHRITE

CHRYSOBERYL

DEMANTOID GARNET

SAPPHIRE GREEN

QUARTZ GR. PRASIOLITE

QUARTZ CHRYSOPRASE

MALACHITE

BLUE
DIAMOND ( very rare )

  • Hardness: 10
  • Color of streak: impossible
  • Density: 3,47-3,55
  • Cleavage: Perfect
  • Crystal System: Cube – octaeder – dodecaeder
  • Chemical composition: Carbon
  • Refractive index: 2.417-2.410
  • Transparency: Transparent to opaque
  • Pleochroism: None
  • Absorption: 4780-41555040
  • Fluorescence: variable
  • Origin: South Africa, Namibia, Congo, Botswana, Russia, Brazil, Canada, Angola, Sierra-Leone, Zimbabwe, Tanzania, Lesotho, …
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BLUE
SAPPHIRE

  • Hardness: 9
  • Color of streak: White
  • Density: 3,95-4,03
  • Cleavage: None
  • Crystal System: Trigonal, doubly pointy, barrel shaped, hexagonal pyramids, tabloid shaped
  • Chemical composition: Aluminum oxide
  • Refractive index: 1,762-1,788
  • Transparency: Transparent to opaque
  • Pleochroism: Dark blue-green blue
  • Absorption: 471-460-450
  • Fluorescence: variable
  • Origin: Thailand, Burma, Sri Lanka, Australia, US (Montana), Cambodia, Kenya, Nigeria, Tanzania, Brazil, China
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BLUE
AQUAMARINE

  • Hardness: 7 ½-8
  • Color of streak: White
  • Density: 2,68-2,74
  • Cleavage: Indistinct
  • Crystal System: Hexagonal prisms
  • Chemical composition: Aluminum beryllium silicate
  • Refractive index: 2.417-2.410
  • Transparency: Transparent to opaque
  • Pleochroism: Colorless, light blue, light green
  • Absorption: 537 456 427
  • Fluorescence: None
  • Origin: Brazil, Burma, Russia, Australia, Madagascar, Mozambique, Namibia, Nigeria, Sri Lanka, India, Kenya, US
Close

RED
DIAMOND ( very very rare )

  • Hardness: 10
  • Color of streak: impossible
  • Density: 3,47-3,55
  • Cleavage: Perfect
  • Crystal System: Cube – octaeder – dodecaeder
  • Chemical composition: Carbon
  • Refractive index: 2.417-2.410
  • Transparency: Transparent to opaque
  • Pleochroism: None
  • Absorption: 4780-41555040
  • Fluorescence: variable
  • Origin: South Africa, Namibia, Congo, Botswana, Russia, Brazil, Canada, Angola, Sierra-Leone, Zimbabwe, Tanzania, Lesotho, …
Close

RED
RUBY

  • Hardness: 9
  • Color of streak: white
  • Density: 3,97 – 4,05
  • Cleavage: None
  • Crystal System: Trigonal – hexagonal prism, rhombohedrons
  • Chemical composition: Aluminum oxide
  • Refractive index: 1.762-1.778
  • Transparency: Transparent to opaque
  • Pleochroism: Strong, yellow-red to deep carmine
  • Absorption: 694-693-476-475-468
  • Fluorescence: Strong red
  • Origin: Thailand, Burma, Sri-Lanka, Tanzania, Afghanistan, Cambodia, Australia, Brazil, India, Kenya, Madagascar, Pakistan, Zimbabwe, Vietnam, US (Montana & North Carolina). Small deposit : Switzerland & Norway
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RED
PINK SAPPHIRE

  • Hardness: 9
  • Density: 3,95 – 4,03
  • Cleavage: None
  • Crystal System: Trigonal – hexagonal prism, rhombohedrons
  • Chemical composition: Aluminum oxide
  • Refractive index: 1.762-1.788
  • Transparency: Transparent to opaque
  • Pleochroism: Blue – none – green
  • Absorption: 471-460-450-
  • Fluorescence: orange-yellow-violet
  • Origin: Thailand, Burma, Sri-Lanka, Tanzania, Afghanistan, Cambodia, Australia, Brazil, India, Kenya, Madagascar, Pakistan, Zimbabwe, Vietnam, US (Montana & North Carolina). Small deposit : Switzerland & Norway
Close

RED
RUBILITE TOURMALINE

  • Hardness: 7 – 7 1/2
  • Density: 2,82 – 3,32
  • Cleavage: Indistinct
  • Crystal System: Trigonal – long crystals
  • Chemical composition: Silicate
  • Refractive index: 1.614-1.660
  • Transparency: Transparent to opaque
  • Pleochroism: Dark-Light red
  • Absorption: 4560-4510
  • Fluorescence: red-violet
  • Origine: Brazil
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GREEN
DIAMOND ( very rare )

  • Hardness: 10
  • Color of streak: impossible
  • Density: 3,47-3,55
  • Cleavage: Perfect
  • Crystal System: Cube – octaeder – dodecaeder –
  • Chemical composition: Carbon
  • Refractive index: 2.417-2.410
  • Transparency: Transparent to opaque
  • Pleochroism: None
  • Absorption: 4780-41555040
  • Fluorescence: variable
  • Origin: South Africa, Namibia, Congo, Botswana, Russia, Brazil, Canada, Angola, Sierra-Leone, Zimbabwe, Tanzania, Lesotho, …
Close

GREEN
EMERALD

  • Hardness: 7,5-8
  • Color of streak: White
  • Density: 2,67-2,78
  • Cleavage: Indistinct
  • Crystal System: Hexagonal prism
  • Chemical composition: Aluminum beryllium, silicate
  • Refractive index: 1,565-1,602
  • Transparency: Transparent to opaque
  • Pleochroism: Green-blue-yellow green
  • Absorption: 683-681-637-630-580-
  • Fluorescence: None
  • Origin: Colombia, Brazil, Pakistan, Zambia, South-Africa, Afghanistan, Australia, Madagascar, India, Ghana, Mozambique, Austria, Malawi, Tanzania, US (Maine, Connecticut, North Carolina)
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GREEN
TOURMALINE GROUP VERDELITE

  • Hardness: 7-7,5
  • Color of streak: White
  • Density: 2,82-3,32
  • Cleavage: Indistinct
  • Crystal System: Trigonal
  • Refractive index: 1,614-1,666
  • Transparency: Transparent to opaque
  • Pleochroism: Green-dark green-yellow green
  • Fluorescence: week to None
  • Origin: Brazil, Sri Lanka, Western and Central Europe
Close

GREEN
AVENTURINE

  • Hardness: 7
  • Color of streak: White
  • Density: 2,64-2,69
  • Cleavage: None
  • Crystal System: Trigonal prism
  • Chemical composition: Silicon dioxide
  • Refractive index: 1,544-1,553
  • Transparency: Translucent to opaque
  • Pleochroism: None
  • Absorption: 682-649
  • Fluorescence: Reddish-Green
  • Origin: Brazil, Tanzania, Ural and Siberia (Russia), India and Austria
Close

GREEN
DIOPSIDE

  • Hardness: 5-6
  • Color of streak: White
  • Density: 3,22-3,38
  • Cleavage: Good
  • Crystal System: Monoclinic
  • Chemical composition: Calcium magnesium silicate
  • Refractive index: 1,664-1,730
  • Transparency: Transparent to translucent
  • Pleochroism: Dark green -yellow green
  • Absorption: 505-493-446-
  • Fluorescence: Violet, orange, yellow, green
  • Origin: India, Burma, Sri Lanka, South Africa, Madagascar, Finland, Austria
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GREEN
DIOPTASE

  • Hardness: 5
  • Color of streak: Green
  • Density: 3,28-3,35
  • Cleavage: Perfect
  • Crystal System: Trigonal
  • Chemical composition: Hydrous copper silicate
  • Refractive index: 1,644-1,709
  • Transparency: Transparent to translucent
  • Pleochroism: Dark to light Green
  • Absorption: 550-465
    Fluorescence: None
  • Origin: Congo, Arizona (US), Russia, Peru, Chile, Namibia, Kyrgyzstan
Close

GREEN
BERYL GREEN

  • Hardness: 7,5-8
  • Color of streak: White
  • Density: 2,78-2,80
  • Cleavage: Indistinct
  • Crystal System: Hexagonal prism
  • Chemical composition: Aluminum beryllium, silicate, with iron
  • Refractive index: 1,565-1,602
  • Transparency: Transparent to opaque
  • Pleochroism: Green-blue-yellow green
  • Fluorescence: None
  • Origin: Ural (Russia), Pakistan, Afghanistan, South Africa, India, South America, China
Close

GREEN
PERIDOT

  • Hardness: 6,5-7
  • Color of streak: White
  • Density: 3,28-,48
  • Cleavage: Indistinct
  • Crystal System: Orthorhombic
  • Chemical composition: magnesium iron silicate
  • Refractive index: 1,650-1,703
  • Transparency: Transparent
  • Pleochroism: Weak: Green-pale green
  • Absorption: 497-495-473-453
  • Fluorescence: None
  • Origin: Egypt, Europe (Norway-Czech Republic) Sri Lanka, Burma, Mexico, Pakistan, Australia, Tanzania, South Africa, Kenya, US (Arizona), Brazil (Minas Gerais)
Close

GREEN
JADE-JADEITE

  • Hardness: 6,5-7
  • Color of streak: White
  • Density: 3,30, 3,38
  • Cleavage: None
  • Crystal System: Monoclinic
  • Chemical composition: Sodium aluminum silicate
  • Refractive index: 1,652-1,688
  • Transparency: Translucent-Opaque
  • Pleochroism: None
  • Absorption: 691-655-630-495-450-437-433
  • Fluorescence: Weak white
  • Origin: Burma, China, Japan, Kazakhstan, Mexico, Canada, Siberia (Russia), California (US)
    Imperial Jade: emerald green
Close

GREEN
JADE-NEPHRITE

  • Hardness: 6-6,5
  • Color of streak: White
  • Density: 2,90-3,03
  • Cleavage: None
  • Crystal System: Monoclinic
  • Chemical composition: calcium magnesium iron silicate
  • Refractive index: 1,600-1,627
  • Transparency: Opaque
  • Pleochroism: Weak: Green-brown green
  • Absorption: 689-509-490-460
  • Fluorescence: None
  • Origin: New Zealand, Brazil, Sinkiang (China), Mexico, Zimbabwe, Taiwan, Australia, Poland, Alaska (US), Canada
Close

GREEN
CHRYSOBERYL

  • Hardness: 8,5
  • Color of streak: White
  • Density: 3,70-3,78
  • Cleavage: Good
  • Crystal System: Orthorhombic
  • Chemical composition: Beryllium aluminum oxide
  • Refractive index: 1,746-1,763
  • Transparency: Opaque
  • Pleochroism: Weak: Green-yellow-red, light green
  • Absorption: 504-495-485-445
  • Fluorescence: None- weak red
  • Origin: Minas Gerais (Brazil), (Urals) Russia, Sri Lanka, Burma, Madagascar, Zimbabwe, US
Close

GREEN
DEMANTOID GARNET

  • Hardness: 6,5-7,5
  • Color of streak: White
  • Density: 2,90-3,03
  • Cleavage: None
  • Crystal System: Cubic, rhombic, dodecahedron, icositetrahedron
  • Chemical composition: calcium, iron silicate
  • Refractive index: 1,600-1,627
  • Transparency: Transparent
  • Pleochroism: none
  • Absorption: 701-693-640-622-443
  • Fluorescence: None -medium
  • Origin: China, Russia, Korea, Congo, US
Close

GREEN
SAPPHIRE

  • Hardness: 9
  • Color of streak: White
  • Density: 3,95-4,03
  • Cleavage: None
  • Crystal System: Trigonal, doubly pointy, barrel-shape, hexagonal pyramids, tabloid shape
  • Chemical composition: aluminum oxide
  • Refractive index: 1,762-1,788
  • Transparency: transparent to Opaque
  • Pleochroism: Green-dark blue/green
  • Absorption: 689-509-490-460
  • Fluorescence: None- blue
  • Origin: Australia, Thailand, Burma, Tanzania, Nigeria, China, Cambodia, Kenya
Close

GREEN
QUARTZ GREEN PRASIOLITE

  • Hardness: 7
  • Color of streak: White
  • Density: 2,65
  • Cleavage: None
  • Crystal System: Hexagonal-trigonal-prisms
  • Chemical composition: Silicon dioxide
  • Refractive index: 1,544-1,553
  • Transparency: Transparent
  • Pleochroism: Weak: Light green- green
  • Fluorescence: None
  • Origin: (Minas Gerais) Brazil, Arizona (US)
Close

GREEN
QUARTZ CHRYSOPRASE

  • Hardness: 6,5-7
  • Color of streak: White
  • Density: 2,58-2,64
  • Cleavage: None
  • Crystal System: Aggregates microcrystalline
  • Chemical composition: Silicon dioxide
  • Refractive index: 1,560-1,540
  • Transparency: Translucent – Opaque
  • Pleochroism: None
  • Absorption: 632-444
  • Fluorescence: None
  • Origin: Madagascar, Urals (Russia), California (US), Brazil, India, New South Wales (Australia), Tanzania, Kazakhstan, South-Africa, Zimbabwe
Close

GREEN
MALACHITE

  • Hardness: 3,5-4
  • Color of streak: Light green
  • Density: 3,25-4,10
  • Cleavage: Perfect
  • Crystal System: Monoclinic, long prismatic
  • Chemical composition: copper carbonate
  • Refractive index: 1,655-1,909
  • Transparency: Opaque
  • Pleochroism: Strong: Green-yellow-dark green
  • Fluorescence: None
  • Origin: Katanga (Congo), Queensland, New South Wales (Australia), Chile, Arizona (US), Zimbabwe
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