Amethyst Stone - Characteristics, Commercialization and Evaluation

Considered the most striking representative of quartz, amethyst has always been coveted.

Queen Catherine the Great had real adoration for this gem.

It was considered, for a long time, a stone as precious as sapphire, diamond and emerald.

raw amethyst
raw amethyst

Today, due to the discovery of abundant deposits, it no longer has much value.

Its value has diminished – but its seductive beauty remains intact.

The violet or purple variety of quartz, amethyst, in addition to being widely used as a gemstone until the XNUMXth century, also has an aura of mysticism around it.

Many "powers" are attributed to her, in different types of cultures. Some people say that the name amethyst comes from an ancient belief that this stone protected its owner from drunkenness.

The name amethyst comes from the Greek term “amethuskein”, where the “a” means not and the “methuskein” means to intoxicate.

However, there are some controversies about the origin of the name.

Its color comes from the presence of iron impurities and aluminum traces, some varieties present the colors by exposure to radiation.

Colors range from light purple or purple to dark, with dark ones with greater transparency being better regarded and, consequently, more expensive.

Some can completely change color if subjected to heat treatment, as you will see later.

Amethyst does not have a uniform color distribution. It appears in fragments, in uneven and/or external corners.

This characteristic often determines the type of cutting for better use of the gem and its value.

Amethysts with perfect color distribution are very rare and, when found, are highly priced.


1. Gemological characteristics

  • Mineral class: quartz
  • Crystal system: trigonal; six-sided prisms
  • Chemical formula: SiO2
  • Hardness: 7 mohs
  • Density: 2,63 - 2,65
  • Transparency: from transparent to translucent
  • Color: violet, purple, light to dark purple
  • Luster: vitreous
  • Fluorescence: weak or absent
  • Fracture: conchoid, brittle

The amethyst is composed of an irregular overlapping of alternating sheets of quartz, on the left and right sides.

As a result of this formation, amethyst can break with a wavy fracture or show “fingerprints”.

Some mineralogists apply the name amethyst to all quartzes that exhibit this structure, regardless of their color. Crystals always grow on a base.

When they are shaped like pyramids, the most intense color predominates at the tips of these crystals.

There are some varieties of amethyst that can feature white streaks of milky quartz.

Amethysts are mostly found in the crystallized crusts of huge volcanic rocks such as basalt.

2. Marketing

The commercialization of amethyst is abundant and with very accessible prices, however, the most beautiful and valuable varieties are found in few places.

These, have deeper colors, purple or violet.

The most important deposits are in Brazil, however, only around 3% of Brazilian amethysts are suitable to be polished and used in jewelry.

The others are used to generate the citrus and also used in decoration or collections. Other important deposits are in Uruguay, India, Russia, Sri Lanka, Madagascar and the United States.

Argentina, Bolivia, Mexico, Namibia, Zambia, South Africa and Canada are also producers of amethyst.

Because they have different tones and nuances, they are usually named after the country of origin, eg. Brazilian amethyst, Bolivian, etc.

3. Evaluation

We've already talked about the 4C's of diamond valuation.

Despite being a classification standard established by the GIA (Gemological Institute of America) for diamonds, it is the most accepted in the world and widely used for other gems and also by several laboratories, gemologists and appraisers.

Color, Carat, Clarity and Cut in Portuguese, color, weight, degree of purity and cut are the 4C's that are used to evaluate amethysts as well.

  • Color

The most valuable amethysts have a strong purple leaning towards reddish and without color zoning, that is, the color is evenly distributed throughout the stone. Very dark amethysts are not as valuable as there is a great deal of reduction in brightness.

The presence of brown or bronze tones in amethysts also reduces its value. To identify, with the naked eye, some color zoning, buyers often place amethyst on a table with a white surface.

  • Degree of purity

Inclusions are one of the factors that determine the purity of amethyst. The lower the number of inclusions, the higher the value and the better the classification.

Most faceted amethysts on the market do not have inclusions that are visible to the naked eye, but they are present in the vast majority of them. Fractures are also commonly found.

  • Weight and Size

The weight of this gem is measured in carats. Like most gemstones, amethysts are found in different sizes and calibrated in millimeters.

Large central stones are extremely used and sold in jewelry stores, as long as the final price is not high.

  • Cutting and Lapping

As we have already said, most amethysts are faceted, in order to make better use of the color distribution and, also, to locate the smallest possible number of inclusions.

If these inclusions are very visible, they are cut into small cabochons or granules.

Amethyst stone jewelry
Amethyst stone jewelry

Oval, pear, emerald, triangular, marquise and cushion cuts are commonly used cuts.

Some arrangements and cut combinations appear in this gem such as step cuts and faceted mixed cuts. There are also variations of cuts called fantasy cuts that exhibit certain concave facets – they are normally mass-produced for certain collections.

Even animal sculptures are made with amethysts. In practice, the color and the degree of purity stand out in the evaluation of amethysts. Due to the high offer, the demand decreases, making it a relatively cheap and easy to buy gem.

However, amethysts do not go out of fashion and are always present, both in expensive jewelry and in cheaper pieces.

4. Varieties of shades

Amethysts have a wide variety of tones according to the place of origin.

Those from Uruguay and Arizona have a deep purple-blue color.

Amethysts from Russia are known as “Siberian” and have very deep colors with reddish and bluish tones.

They originate from deposits that have already been depleted and therefore have a higher price.

Africa produces amethysts with deeper colors than Brazil and other South American countries.

The term African amethyst can be used to designate amethysts with different shades or darker, but this does not always mean that this is their origin.

Brazil is considered the largest producer of amethysts, although most Brazilian amethysts are treated and sold as heated citrine. Here the stones are available in all sizes and shapes.

The colors are not as good as those in Africa, but they meet the market demand.

5. Treatments and synthetics

Heat treatment can be used to lighten the color of the amethyst when it is too dark, darken it when it is light, or remove brownish inclusions.

Ultraviolet radiation is also used to enhance or change the color of amethysts.

Fracture treatments are rarely performed, due to the high availability of specimens that do not present them to the naked eye.

The thermal treatment causes an expansion of the inclusions, which can generate fractures in the gem, it also increases the color zoning effect.

Typically, zoning inclusions and expansions are used to differentiate a treated amethyst from an untreated or synthetic one.


When amethyst is heated to high temperatures, around 470°C to 750°C, iron impurities are reduced, resulting in heated citrine.

Although this treatment is highly used, the color obtained from the citrus it is not always permanent.

Citrine, also called citrine quartz (there are several other inappropriate names, such as citrine-topaz) is a variety of yellow, orange colored quartz, exceptionally red. Basically, it is a quartz with ferric impurities.

Most commercial citrine is actually amethyst or artificially heated smoky quartz.

However, heat-treated stone may present differences, including a pinker color characteristic of the original stone. The commercial value, however, is the same, at least in Brazil. Citrine quartz is a low-priced gemstone, cheaper than amethyst, but still highly prized and often used in jewelry. Brazil and Scotland are the world's largest citrus fruit producers. Brazil leads in the production of amethyst, rose quartz and clear quartz, with much of the production coming from Rio Grande do Sul. This variety of quartz is often used as a substitute for many yellow gemstones such as topaz or sapphires.

Synthetic amethysts can be produced using hydrothermal methods, in which case small fragments of quartz and a solution of calcium carbonate, for example, are placed in a sealed container under high pressure.

This causes the crystals to melt and recrystallize upon heating.

Some specialists in gemstones say that synthetic amethysts are widely mixed, on the market, with natural ones, but as identification tests – in their case – are not widely used, it cannot be said.

Others say supply is so high that production of synthetics is limited to use in radios, watches and other electrical appliances.

Therapeutic properties

In ancient times, amethyst was widely used to protect individuals from drunkenness and intoxication, hence the name.

Today, people wear amethysts to keep the faith, bring peace and calm the spirit. They say it strengthens wisdom and religiosity.

It prevents one from having evil thoughts and actions, gives sensitivity in business and good health.

Oriental women use it on the forehead and believe that it gives positive energy to the Ajna chakra, also known as the "third eye".


Amethyst is a very durable stone, but care must be taken to remove the jewel in activities where the stone may be at risk.

It is important not to expose it to intense sunlight for a long time, radiation or black light. It can be easily cleaned with warm water and mild soap, with a soft cloth or toothbrush. When storing, care must be taken not to place it together with other harder stones, as scratches are inevitable.

Do not use chemical and abrasive products. The ideal is to wrap it in a soft cloth or a box lined with fabric.

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