Ruby

Rubies are a lovely red gemstone famous for their use in jewellery. Many of the mineral specimens are of a lower quality than the gemstone grade specimens.

They are often inclusions in other minerals, such as fuchsite or Zoisite. Rubies make an excellent display piece, with good colours and usually good UV fluorescence too!

We do also sell a limited selection of Rubies for jewellery making.

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Appearance, Uses and History

Ruby is a gemstone variant of Corundum, and one of the worlds most beloved gemstones.

It is important to note that many people will consider pink-red stones Ruby, too – however, this is a hotly debated subject. The term ‘Sapphire’ refers to the other colours of gem Corundum.

It is a little difficult to get a handle on exactly where the distinction occurs, however, and for mineral specimens, I tend to refer to them as ‘red Corundum’.

The quality of a Ruby is determined by their colour, cut, clarity, and carat weight – the ‘4 C’s‘.

Ruby is typically used as a decorative stone or a gemstone – although there are uses in industry, these are typically done with synthetic Corundum.

 

Locales

Excellent mineral specimens (and some cuttable stones) are found in Afghanistan, Australia, Burma, India, Kenya, Madagascar, Mozambique, Myanmar, Nepal, Norway, Pakistan, Russia, Sri Lanka, Tanzania, the USA, and Vietnam.

Mineralogy

Chemistry
Aluminium Oxide crystals, coloured by Chromium. Al2O3,Cr
Colours and Variations
Red, purple-red, orange-red, pink-red.
Streak
White
Luster
Subadmantine, vitreous
Fracture
Conchoidal, splintery
Crystal habit
Tabular hexagonal crystals.
Mohs hardness
9
Specific Gravity
3.95 – 4.05
Easiest testing method
UV light can be a good indicator but there are so many synthetics it is best to get Rubies professionally tested.
Common Treatments
The most common treatment is heat treatment, but there have been other treatments too – including lead glass filling.

Hazards and Warnings

Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis.

When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.

Translations

Arabic:

  • ياقوت

Hindi:

  • माणिक

Portuguese:

  • Rubin
  • rubi

Bengali:

  • চুনি

Indonesian:

  • Rubi

Punjabi:

  • ਰੂਬੀ ਰਤਨ

English:

Italian:

  • Rubino

Russian:

  • Рубин

French:

  • Rubis

Japanese:

  • ルビー

Spanish:

  • Rubí

German:

  • Rubin

Korean:

  • 루비

Thai:

  • พลอยทับทิม

Gujurati:

  • રૂબી રત્ન

Mandarin and Traditional Chinese:

  • 红宝石宝石
  • 紅寶石寶石

Urdu:

  • روبی

Further Reading / External Links