Turquoise has captivated humans for millennia, from ancient Persian royalty to modern jewellery enthusiasts. This stunning blue-green gemstone carries with it a rich history and, unfortunately, a complex world of imitations and treatments that can confuse even experienced collectors. Whether you’re a jewellery lover, collector, or simply curious about this beautiful stone, understanding what makes real turquoise special—and how to spot the fakes—is essential knowledge in today’s market.

What is Turquoise?

At its core, turquoise is a hydrated aluminium phosphate mineral with the chemical formula CuAl₆[PO₄(OH)₂]₄·4H₂O. But let’s break that down into simpler terms: it’s essentially a mineral formed when copper, aluminium, and phosphate combine with water over long periods. The beautiful blue colour that makes turquoise so desirable comes from copper content, while iron creates the green variations we sometimes see.

Turquoise has a hardness of about 6 on the Mohs scale, making it relatively soft compared to other gemstones like quartz. This softness, while making it easier to work with, also makes it more susceptible to damage and wear over time.

The Many Colours and Types of Turquoise

Colour Variations

Turquoise naturally occurs in a wide spectrum of colours:

• Sky blue: The most prized and valuable variety
• Blue-green: Very common and popular
• Green-yellow: Less valuable but still attractive
• Grey-green: Lower quality
• Navy blue: Rare variety
• Blue-white: Often lower grade

The colour depends largely on the mineral content. High copper content produces the coveted sky-blue colour, while iron creates greener tones. Aluminium-rich stones tend toward white or pale colours.

Matrix Patterns

One of turquoise’s most distinctive features is its matrix—the host rock that often appears as veins running through the stone. These patterns can be:

• Spider web patterns: Intricate, web-like veins that are highly prized when well-formed
• Irregular spots and patches: Less desirable when chaotic
• Clean stones: The rarest and most valuable type, called “Ajam turquoise,” can sell for over $1,000 per gram

Common Turquoise Imitations: Know What You’re Buying

The popularity and value of turquoise have led to numerous imitations flooding the market. Here are the most common impostors and how to spot them:

1. Chrysocolla

What it is: A copper silicate mineral that looks remarkably similar to turquoise

How to spot it:

• Lower density (1.9-2.4) compared to turquoise (2.6)
• Lacks fluorescence under UV light (turquoise shows normal fluorescence)
• Has a concentric, layered structure visible under magnification

2. Dyed Howlite

What it is: A porous calcium borosilicate mineral that easily absorbs dye

How to spot it:

• Similar density to turquoise, making weight tests unreliable
• Lacks natural inclusions seen in real turquoise
• May show uneven dye distribution under magnification
• A cotton swab with acetone can reveal artificial colouring (though this is destructive)

3. Malachite

What it is: A copper carbonate mineral with distinctive banded patterns

How to spot it:

• Much higher density (3.6) than turquoise
• Shows characteristic concentric bands and zones
• Lower hardness than turquoise
• Different associated minerals in the host rock

4. Variscite

What it is: An aluminium phosphate mineral often found with turquoise

How to spot it:

• Very weak fluorescence compared to turquoise’s stronger glow
• Different green colour tone (requires experience to distinguish)
• May show crystalline formations not typical in turquoise

5. Plastic Imitations

What it is: Moulded plastic designed to mimic turquoise

How to spot it:

• Extremely lightweight
• May show mould lines
• Uniform colour without natural variations
• Different feel when handled

Advanced Synthetic Turquoise

Gilson Synthetic Turquoise

Created by the Gilson company in France, this synthetic turquoise has properties very close to natural stone. The giveaway is often an unusually perfect polish and colour that’s too vibrant and consistent for natural turquoise. To know more about it, click here.

Neolite Composite Turquoise

A newer synthetic material made from copper phosphate, barite, and gibbsite. Unlike natural turquoise, it shows no reaction under UV light.

Fossil “Turquoise”

Not actually turquoise at all, but fossilised bone or teeth colored by iron or copper phosphates. These are much lighter than real turquoise and show organic textures under magnification.

Treatment Methods: What Happens to Natural Turquoise

Even genuine turquoise is often treated to improve its appearance and durability. Understanding these treatments helps you make informed purchasing decisions:

1. Waxing and Oiling

• Purpose: Enhance colour and add surface shine
• Method: Applying wax or oil to the surface
• Detection: May show white residue when heated or exposed to strong sunlight
• Impact: Temporary improvement that can fade over time

2. Stabilisation

• Purpose: Increase hardness and prevent colour change
• Method: Impregnating porous turquoise with resins under pressure and heat
• Materials used: Epoxy resins, plastics, or clear glass solutions
• Detection: Often creates a slightly artificial-looking wet appearance

3. Reconstitution

• Purpose: Create larger stones from small fragments
• Method: Bonding together small pieces of natural turquoise with adhesives
• Detection: Visible boundaries between pieces under magnification
• Note: Has spawned an art form called “turquoise inlay” that’s popular in traditional crafts

4. Dyeing

• Purpose: Improve or change colour
• Method: Applying artificial colours to enhance or alter natural hues
• Detection: Often shows unusually dark or uniform colouration
• Risk: Can be nearly impossible to detect with advanced techniques

5. Backing

• Purpose: Strengthen thin, fragile turquoise slabs
• Method: Gluing a strong backing material to the thin turquoise
• Common in: Nevada turquoise, which often occurs in very thin layers
• Materials: Originally, old batteries and gramophone record powder; now synthetic resins
• Impact: Doesn’t increase value but makes otherwise unusable material workable

How to Identify Treatments and Imitations

Quick Tests You Can Do:

1. UV Light Test: Natural turquoise typically shows fluorescence; many imitations don’t
2. Weight Feel: Natural turquoise has a specific density that experienced handlers can recognise
3. Visual Inspection: Look for overly perfect colours, artificial shine, or obvious seams in reconstituted pieces

Professional Methods:

• Microscopic examination: Reveals internal structure and treatment evidence
• Specific gravity testing: Measures exact density
• Refractive index testing: Determines how light bends through the stone
• Spectroscopic analysis: Identifies the exact chemical composition

Market Value and Quality Factors

The value of turquoise depends on several factors:

Premium Qualities:

• Pure sky-blue colour without green tinting
• Absence of matrix (clean stones)
• Good hardness (less porous stones)
• Large size without cracks or flaws
• Natural state (untreated stones command premiums)

Location Matters:

Different mines produce turquoise with distinct characteristics. Persian turquoise, particularly from Neyshabur (Nishapur), has historically been among the most prized, while American turquoise from Nevada, Arizona, and New Mexico each has unique matrix patterns and colours.

Caring for Your Turquoise

Turquoise requires special care due to its relative softness and porosity:

• Avoid chemicals: Keep away from perfumes, lotions, and cleaning products
• Protect from heat: High temperatures can cause colour changes or crack treatments
• Gentle cleaning: Use only mild soap and soft brushes
• Proper storage: Store separately to avoid scratches from harder gemstones
• Professional maintenance: Have valuable pieces checked periodically for treatment degradation

The Bottom Line: Buying Smart

When purchasing turquoise:

1. Buy from reputable dealers who disclose treatments
2. Ask for documentation of any treatments or enhancements
3. Consider your intended use: Heavily treated stones may be fine for costume jewellery, but aren’t suitable for serious collecting
4. Learn to appreciate different qualities: Not all turquoise needs to be gem-grade to be beautiful
5. Get expensive pieces professionally evaluated before purchasing

Conclusion

Turquoise remains one of humanity’s most beloved gemstones, but the modern market requires educated consumers. Understanding the difference between natural stones, treated materials, and outright imitations protects you from disappointment and financial loss while helping you appreciate the true beauty of this ancient gem.

Whether you choose a natural stone with its unique imperfections, a stabilised piece for daily wear, or even a well-made synthetic for an affordable option, knowing what you’re buying ensures you get exactly what you expect. The key is honest disclosure from sellers and informed decisions from buyers.

Remember that each piece of turquoise tells a story—whether it’s millions of years in the making naturally, or crafted in a modern laboratory. Both have their place in the world of gems, as long as everyone knows which story they’re buying.

Author: Sohrab Jamarani
Amitis Art