How Do You Make Turquoise

How Do You Make Turquoise? Unveiling the Secrets of This Ancient Gemstone

Turquoise, with its captivating blue-green hues, has captivated civilizations for millennia. This highly prized gemstone, prized for its beauty and cultural significance, isn't simply dug from the earth in its perfect form. The creation of turquoise, both naturally and, to a lesser extent, synthetically, is a complex process involving geological forces and, in the case of man-made turquoise, careful chemical manipulation. This article delves into the fascinating world of turquoise formation, exploring both the natural and synthetic creation processes to offer a comprehensive understanding of this beloved gem.

Understanding Natural Turquoise Formation: A Geological Perspective

Natural turquoise, chemically known as hydrated copper aluminium phosphate, is a secondary mineral, meaning it forms from the alteration of pre-existing rocks. Its formation is a complex process involving several crucial factors:

• Source Materials: The genesis of turquoise begins with the presence of copper-bearing minerals and aluminum-rich rocks, usually within arid or semi-arid environments. These rocks often contain minerals like feldspar and apatite, which provide the necessary phosphorus and aluminum.

• Water Interaction: Water plays a vital role. Groundwater, percolating through the copper and aluminum-rich rocks, leaches out these elements. This process is crucial; the water acts as a solvent, dissolving the copper and aluminum compounds.

• Phosphorous Source: The dissolved copper and aluminum ions then combine with phosphate ions, often originating from the weathering of apatite. The exact source of phosphate can vary, contributing to the diversity in turquoise color and quality.

• Precipitation and Crystallization: As the water evaporates, or encounters a change in chemical conditions, the dissolved copper, aluminum, and phosphate ions precipitate out of solution. This precipitation leads to the formation of turquoise crystals. The crystals typically aggregate to form the characteristic nodules, veins, and masses found in turquoise deposits.

• Geological Conditions: The specific geological environment significantly influences the final color and quality of the turquoise. Factors like pH, temperature, and the presence of other elements (e.g., iron, zinc) can impact the final hue and clarity of the gem. For instance, iron impurities can lead to a greenish tint, while the absence of impurities can result in a vibrant, intense blue.

Turquoise's Diverse Colors: A Spectrum of Hues

The captivating color range of turquoise, from a sky-blue to a deep greenish-blue, is not merely aesthetic but reflects its chemical composition and the geological conditions under which it formed.

• Blue Turquoise: The intense blue color is characteristic of turquoise with a high copper content and a low concentration of impurities. These gems are highly sought after.

• Greenish-Blue Turquoise: A greenish hue often indicates the presence of iron impurities within the crystal structure. While less prized than intense blue turquoise, greenish-blue stones still maintain a significant appeal.

• Matrix Turquoise: This type features turquoise interspersed with other minerals, creating interesting patterns and textures. The matrix material can be a variety of rocks, including limestone, iron oxides, and quartz. The matrix adds to the uniqueness of each piece.

The Synthetic Creation of Turquoise: Mimicking Nature's Masterpiece

While natural turquoise remains the most valued, synthetic turquoise also exists. The creation of synthetic turquoise involves replicating the chemical composition and crystal structure of the natural gem in a controlled laboratory environment. There are two primary methods employed:

1. The Precipitation Method: A Chemical Approach

This method mimics the natural process of turquoise formation. It involves carefully controlling the chemical reaction between copper salts, aluminum salts, and phosphate sources in an aqueous solution. The precise control of pH, temperature, and the concentration of reactants is critical to achieving the desired color and crystal structure. This method allows for the production of turquoise with consistent color and quality, unlike the variations found in naturally occurring turquoise. However, the resulting synthetic turquoise may not always perfectly replicate the natural mineral’s complex matrix and internal structures.

2. The Hydrothermal Method: High-Pressure Synthesis

The hydrothermal method uses high temperatures and pressures to accelerate the crystal growth process. This method typically involves placing the precursor materials (copper, aluminum, and phosphate compounds) within a sealed container filled with a water-rich solution. The container is then heated to high temperatures (often exceeding 200°C) and subjected to high pressure. Under these conditions, the turquoise crystals grow faster and larger than in the precipitation method. This allows for the creation of larger, more uniform stones.

Distinguishing Natural from Synthetic Turquoise: Key Differences

Identifying whether a piece of turquoise is natural or synthetic requires careful examination. While experienced gemologists employ advanced techniques, some visual clues can help:

• Color Consistency: Synthetic turquoise often exhibits a greater uniformity in color compared to the natural variations often seen in natural stones.

• Inclusions: Natural turquoise usually contains inclusions (small mineral particles or flaws) while synthetic turquoise tends to have fewer, or more uniform inclusions.

• Fluorescence: Under ultraviolet (UV) light, natural and synthetic turquoise often exhibit different fluorescence patterns.

• Density and Refractive Index: These properties, measured using specialized instruments, can provide crucial differentiating data.

• Matrix: The presence of a visible matrix (other minerals interspersed with the turquoise) is more characteristic of natural turquoise.

Frequently Asked Questions (FAQs)

Q: Where is turquoise found?

A: Turquoise deposits are found globally, but some of the most significant sources include Iran, the southwestern United States (Arizona, Nevada, New Mexico, Colorado), and Chile.

Q: Is synthetic turquoise valuable?

A: Synthetic turquoise has less value than natural turquoise because it lacks the geological history and natural variations that are prized by collectors and enthusiasts. However, synthetic turquoise can be a more affordable alternative for those wanting the aesthetic appeal of the gem.

Q: How is turquoise cared for?

A: Turquoise is a relatively soft gemstone (Mohs hardness of 5-6), so it's susceptible to scratching. Avoid harsh chemicals and ultrasonic cleaning. Clean gently with a soft cloth and mild soap.

Q: What is the difference between turquoise and howlite dyed to look like turquoise?

A: Howlite is a naturally occurring mineral that is often dyed to imitate the appearance of turquoise. However, howlite is considerably softer and porous than turquoise, making it easier to identify. The dye can also fade or wear off over time, unlike the inherent color of true turquoise.

Conclusion: The Enduring Allure of Turquoise

Turquoise, whether formed naturally through complex geological processes or created synthetically through precise chemical manipulation, remains a gemstone of remarkable beauty and cultural importance. Understanding the methods of its creation, both natural and artificial, deepens our appreciation for its unique properties and the craftsmanship involved in shaping this ancient gem into jewelry and decorative objects. Whether you are an admirer, a collector, or a lapidary, knowing the journey of turquoise from geological formation to the finished product enhances the value and meaning of this exquisite gemstone. The allure of turquoise continues to captivate, a testament to its enduring beauty and the mysteries it holds within its captivating blue-green depths.