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Topaz

Honey yellow. Fiery orange. Cyclamen pink. Icy blue. In warm or cool tones, topaz is a lustrous and brilliant gem.

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Reddish Pleochroism

Topaz’s reddish pleochroic colour often appears at the ends of cut gems.

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Prized Colour

Rich reddish orange is one of this gem's most coveted colours.

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Long Oval

Because topaz crystals are typically elongated, polished gems are often cut long.

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Columnar Crystal

This topaz crystal has a columnar prism with a “chisel-like” termination.

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Basal Cleavage

Parallel to the base of the crystal are weaker bonds between the atoms.

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Imperial

The colour the trade calls imperial topaz is highly prized and very rare.

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Tools

Overview

About Topaz

29 imperial topaz gems

Topaz actually has an exceptionally wide colour range that, besides brown, includes various tones and saturations of blue, green, yellow, orange, red, pink, and purple. Colourless topaz is plentiful, and is often treated to give it a blue colour. Topaz is also pleochroic, meaning that the gem can show different colours in different crystal directions.

Topaz Description

Topaz History and Lore

Topaz Journey


Birthstones & Anniversaries

Precious topaz is a birthstone for November and blue topaz is a birthstone for December. Blue topaz is the gem of the 4th anniversary and Imperial topaz is the gem of the 23rd anniversary.

1768

The royal court in Portugal celebrates the discovery of Imperial topaz in 1768.


271 kilos

A transparent topaz crystal discovered in Minas Gerais, Brazil weighs an astounding 596 pounds.


10 MeV

Irradiating colourless topaz with electrons at energy of 10 million electron volts creates a sky blue colour.


Facts

  • Mineral: Topaz
  • Chemistry: Al2(F,OH)2SiO4
  • Colour: Yellow, orange, brown, pink to red to purple red, blue, light green and colourless
  • Refractive index: 1.619 to 1.627
  • Birefringence: 0.008 to 0.010
  • Specific gravity: 3.53
  • Mohs hardness: 8

Treatments

There are a number of processes used to alter the colour or apparent clarity, or to improve the durability of gems.

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Synthetics

Some gemstones have synthetic counterparts that have essentially the same chemical, physical and optical properties, but are grown by man in a laboratory.

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Imitations

Any gem can be imitated – sometimes by man-made materials or by natural materials chosen by man to impersonate a particular gem.

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gem love

Why We Love This Gemstone

1
Kilos

Topaz comes in some of the gem world’s largest crystals: the largest are kilos, not carats.

2
Slippery

Faceted topaz takes such a high polish it’s slightly slippery to the touch.

3
Pleochroic

Topaz is pleochroic, displaying different colours in different crystal directions.

Quality Factors

Topaz comes in a variety of colours from shades of blue to the rare reddish imperial colours.

Colour

quality factors

The most valued topaz colours are orangey red to red. Blue gems are widely available.

Clarity

quality factors

Topaz used in jewellery is typically eye clean with no visible inclusions.

Cut

quality factors

Topaz crystals are usually columnar, and cut as oval or pear shapes to improve yield.

Carat Weight

quality factors

Topaz often forms as large crystals. These can yield sizeable cut gems.

Topaz Quality Factors: The Comprehensive Guide

Research

Explore sources, gemmological research and the role of gems in history.

Topaz from Pakistan with microlite inclusions.

Microlite Crystals in Topaz from Pakistan

Jaroslav Hyršl , Aug 9, 2018 Read more in English

Cutting the ‘Imperial Flame’ Topaz

Duncan Pay , Apr 28, 2016 Read Article
Brazilian colorless topaz with molybdenite inclusions.

Molybdenite in Topaz

John I. Koivula , Nov 23, 2015 Read more in English

Quarterly Crystal: Triplite in Topaz

John I. Koivula , Aug 3, 2016 Read more in English

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