Number 8 Turquoise stands as a distinct category within the world of collectible gemstones, celebrated for its unique visual characteristics and historical provenance. For serious collectors, understanding the nuances of this specific material is critical for accurate identification, valuation, and long-term preservation. This guide provides a detailed framework for distinguishing authentic Number 8 Turquoise, assessing its quality, and integrating it strategically into a collection. The commercial utility of this knowledge lies in preventing misidentification, ensuring fair pricing, and ultimately protecting the integrity and value of an investment.
What Defines Number 8 Turquoise?
Originally mined in Carlin, Nevada, the Number 8 mine operated primarily from the 1920s to the 1970s, producing a limited supply of turquoise that quickly gained recognition for its distinctive appearance. Its scarcity, combined with its aesthetic appeal, underpins its high value in the market today.
Key Visual Attributes
The hallmark of Number 8 Turquoise is its spiderweb matrix. This refers to a fine, intricate web-like pattern of host rock (often limonite or chert) running through the turquoise. While other turquoises exhibit matrix, Number 8's is typically fine, dense, and often black, brown, or golden-brown, creating a stark contrast with the stone's blue. The blue itself varies, ranging from a sky blue to a deep, intense royal blue, occasionally with hints of green. High-grade specimens often display a vibrant, consistent blue with a well-defined, tight spiderweb matrix.
Geological Context and Rarity
The specific geological conditions at the Number 8 mine created the unique mineral composition and matrix patterns. The mine's closure means no new material is being extracted, making existing specimens finite. This finite supply directly contributes to its rarity and, consequently, its elevated market price compared to more commonly available turquoise varieties. Collectors primarily encounter Number 8 Turquoise in pre-owned jewelry, estate sales, or through specialized dealers who have acquired older stock.
Identifying Authentic Number 8 Turquoise
Authentication requires a keen eye and familiarity with the material's specific characteristics, as fakes and mislabeled stones are prevalent.
Understanding Matrix Patterns
Examine the matrix closely. Authentic Number 8 often features a very thin, delicate, yet clearly defined spiderweb. The colors of the matrix are typically black, golden-brown, or reddish-brown. Be wary of overly thick, crude, or inconsistent matrix patterns, which can indicate a different type of turquoise or even a manufactured imitation. The spiderweb should appear natural and integrated, not painted or superficial.
Color Variations and Luster
The blue of Number 8 Turquoise is usually bright and clear, often described as a robin's egg blue or a deep sky blue. Some specimens may show subtle green undertones, but the dominant hue is blue. The stone should exhibit a natural, waxy to sub-vitreous luster when polished. Avoid stones with an unnaturally uniform, plastic-like sheen or dull, chalky appearance, which can suggest stabilization, dyeing, or reconstruction.
Weight and Density Considerations
Turquoise has a specific gravity ranging from 2.6 to 2.9. While difficult to assess without specialized equipment, an experienced collector can often feel the difference between natural, dense turquoise and lighter, more porous imitations or composites. Genuine turquoise feels solid and cool to the touch. Reconstituted or plastic imitations often feel lighter or warmer.
Pro Tip: Always scrutinize the reverse side of a cabochon or cut stone. Authentic Number 8 Turquoise often shows natural inclusions, slight irregularities, or evidence of the original rough stone. A perfectly smooth, uniform back can sometimes indicate a manufactured composite or a thin veneer applied to a backing material.
Grading and Valuation Factors
Valuation of Number 8 Turquoise extends beyond mere authenticity, incorporating several quality metrics.
The Role of Hardness and Stability
Natural turquoise is relatively soft (5-6 on the Mohs scale). High-grade Number 8 Turquoise is typically hard enough to be cut and polished without stabilization treatments. Unstabilized, natural stones command the highest prices. Stabilization, while common for many turquoise varieties, involves impregnating porous turquoise with epoxies to enhance hardness and color. While not inherently "bad," stabilized Number 8 Turquoise is valued significantly less than natural, untreated material. Always inquire about treatment status.
Cut, Polish, and Presentation
The quality of the cut and polish significantly impacts value. Well-cut cabochons display the matrix pattern optimally, have smooth, symmetrical domes, and show no pits or scratches. The polish should be consistent and lustrous, enhancing the stone's natural beauty without appearing artificial. Stones set in high-quality, period-appropriate jewelry (e.g., vintage Native American silverwork) can also command a premium due to the combined artistry and historical context.
Provenance and Documentation
Documented provenance—a clear history of ownership or origin—adds considerable value and confidence. Certificates of authenticity from reputable gemological laboratories or established dealers, especially those specializing in antique or collectible turquoise, can verify the stone's origin and treatment status. For significant pieces, detailed records of acquisition and previous appraisals are invaluable.
Caring for Your Number 8 Turquoise
Proper care is essential to maintain the stone's beauty and value.
Cleaning and Storage Best Practices
Turquoise is porous and can absorb oils, lotions, and chemicals, leading to discoloration. Clean Number 8 Turquoise gently with a soft, dry cloth. For occasional deeper cleaning, use a very mild, non-abrasive soap diluted in distilled water, applied sparingly with a soft brush, and immediately dried. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. Store turquoise separately from harder gemstones to prevent scratching. Keep it away from direct sunlight and extreme temperature fluctuations, which can cause fading or cracking.
Avoiding Damage and Degradation
- Remove turquoise jewelry before engaging in activities that involve chemicals (e.g., cleaning, swimming).
- Avoid prolonged exposure to water, as it can cause the stone to absorb moisture and change color.
- Protect from impacts; despite its hardness, turquoise can chip or crack if struck.
- Do not expose to high heat, which can alter color or cause structural damage.
Building a Number 8 Turquoise Collection
A strategic approach ensures both aesthetic satisfaction and potential investment growth.
Sourcing Reputable Dealers
Acquire Number 8 Turquoise from dealers with established reputations and specialized knowledge of collectible turquoise. Look for dealers who provide detailed descriptions, clear photographs, and a transparent return policy. Attend reputable gem shows, antique fairs, and auctions where expert verification is often available. Be wary of deals that seem too good to be true, as they often are.
Investment Potential and Market Trends
High-grade, natural, untreated Number 8 Turquoise has shown consistent appreciation in value due to its rarity and historical significance. The market for collectible turquoise is driven by both aesthetic demand and the finite supply. Monitoring auction results and consulting with experienced collectors or appraisers can provide insight into current market trends and help inform purchasing decisions. Focus on quality over quantity, prioritizing stones with exceptional color, matrix, and provenance.
Practical Considerations for Collectors
Successful collection of Number 8 Turquoise hinges on informed decisions at every stage, from initial identification to long-term preservation. Prioritize education about the stone's specific characteristics and market dynamics. Cultivate relationships with knowledgeable dealers and other collectors to leverage shared expertise. Regular inspection and appropriate care will ensure that your Number 8 Turquoise maintains its visual appeal and intrinsic value for years to come.
Frequently Asked Questions
Is all Number 8 Turquoise blue?
While predominantly blue, ranging from sky blue to deep royal blue, some specimens may exhibit slight greenish undertones. The characteristic spiderweb matrix is more consistent than the exact shade of blue.
How can I tell if my Number 8 Turquoise is stabilized?
Stabilized turquoise often has a more uniform, sometimes plastic-like appearance and a slightly higher sheen. Untreated turquoise typically has a more natural, waxy luster and may show subtle variations in texture or porosity. A professional gemologist can confirm treatment status.
What makes Number 8 Turquoise more valuable than other types of turquoise?
Its primary value drivers are its unique and highly desirable spiderweb matrix, vibrant blue colors, and extreme rarity due to the mine's closure. The finite supply and distinct aesthetic contribute to its premium status among collectors.
Can Number 8 Turquoise change color over time?
Yes, natural turquoise is porous and can change color due to absorption of oils, lotions, and chemicals, or prolonged exposure to sunlight and heat. This is why proper care and storage are crucial for preserving its original hue.
