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RAW MATERIAL

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Natural Stone Blocks

Premium natural stone blocks selected for international export.

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PROJECT-READY STONE

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Cut-to-Size Stone

Precision-cut natural stone for architectural and commercial projects.

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onyx blocks

Onyx blocks are among the most distinctive raw materials in the natural stone industry. Unlike many dimension-stone products that are primarily evaluated by background color and structural performance, onyx is often purchased because of the relationship between color, translucency, mineral layering, veining, internal movement and the visual effect that emerges after the block is transformed into slabs.

For international buyers, however, buying onyx blocks requires considerably more than selecting an attractive photograph.

The appearance of a finished onyx slab begins inside the quarry block. The direction in which the block is cut, the geological layering, the distribution of translucent and opaque zones, the presence of fractures, the internal structure, the usable recovery and the treatment required during slab production can all influence the final commercial value of the material.

This is why professional onyx procurement starts with the block rather than the finished photograph.

USGS defines dimension stone as natural rock quarried to obtain blocks or slabs that meet specifications for dimensions and shape, while color, grain, texture and pattern are also normal selection requirements. Durability, strength and the ability to take a polish are additional considerations.

Onyx adds another level of complexity because its visual character can be highly dependent on geological structure and cutting orientation.

For importers, distributors, fabricators, architects, hospitality developers and luxury-project buyers, the right onyx block is therefore not simply the block with the most dramatic surface. It is the block whose geological structure, dimensions, visual potential, recovery and technical characteristics are appropriate for the intended finished product.

What Are Onyx Blocks?

Onyx blocks are quarried natural-stone blocks intended for further processing into slabs, tiles, cut-to-size components, decorative panels, furniture elements and other architectural products.

In the commercial natural-stone market, the term “onyx” can encompass materials that are marketed according to their visual and commercial characteristics rather than solely according to strict geological classification.

Natural Stone Institute notes that onyx is particularly valued for its color and veining and is widely recognized for its translucent properties, which can create distinctive effects when the finished material is backlit. It also notes that commercial onyx has historically been marketed as marble despite its differences from true marble.

This distinction is important for professional procurement.

A buyer should not evaluate an onyx block solely by its commercial name.

The specification should establish the actual material, its appearance, intended application, physical characteristics where relevant, and the processing required to convert the block into the final architectural product.

Why the Onyx Block Matters More Than the Photograph

A finished slab photograph shows only one plane of a much larger geological structure.

An onyx block contains three-dimensional information that may not be visible in a single image.

Inside the block, there may be:

• Parallel mineral bands
• Curved or irregular veining
• Translucent layers
• Opaque zones
• Color transitions
• Natural cavities
• Fractures
• Internal discontinuities
• Changes in background tone
• Variations in mineral concentration

When the block is sawn, these structures become visible across a sequence of slabs.

This means that the commercial value of a block can depend on what the producer expects to obtain from it.

A block that looks relatively modest on its exterior may produce highly attractive slabs after the correct cutting direction is selected.

Conversely, a block with a spectacular exposed face may contain internal fractures or unfavorable geometry that reduces its practical recovery.

Professional block selection therefore requires both visual judgment and technical judgment.

Geological Character of Onyx

Natural onyx is valued for its layered appearance and mineral movement.

The exact geological composition and characteristics depend on the source. Commercially marketed onyx can display translucent bands, contrasting colors, organic patterns and dramatic internal structures.

Common visual families can include:

• White onyx
• Cream onyx
• Honey onyx
• Golden onyx
• Green onyx
• Beige onyx
• Pink onyx
• Red-toned onyx
• Brown onyx
• Multi-color onyx

These commercial categories should not be treated as universal geological classifications.

Two materials sold under similar commercial names may behave differently during processing and may produce significantly different visual results.

For international procurement, the material should therefore be identified through actual samples, source information, photographs and, where required, technical documentation.

Translucency: The Defining Commercial Character of Onyx

One of the most important characteristics associated with onyx is translucency.

Natural Stone Institute specifically identifies translucent properties as a major reason onyx is valued in architectural applications, particularly where backlighting can produce dramatic visual effects.

This characteristic creates opportunities that are less common with many conventional dimension stones.

When light is introduced behind an appropriately selected onyx slab, areas of different thickness, density, mineral concentration and color can interact with the light source.

The result can reveal:

• Layering
• Vein structures
• Color gradients
• Translucent zones
• Internal mineral patterns
• Depth

However, not every onyx block has identical translucency.

Even within one commercial variety, the degree of light transmission can vary across the block.

Therefore, if backlighting is a critical part of the project, the buyer should specify translucency as part of the selection process rather than assuming that every block marketed as onyx will perform identically.

Selecting Onyx Blocks for Backlit Projects

Backlit applications require a more specialized selection strategy.

The buyer should evaluate:

1. Overall translucency
2. Distribution of translucent zones
3. Color under transmitted light
4. Thickness
5. Internal structure
6. Surface treatment
7. Reinforcement requirements
8. Resin treatment where applicable
9. Slab dimensions
10. Lighting system compatibility

The visual result should ideally be evaluated using a representative slab sample under lighting conditions similar to the final installation.

A photograph of a polished slab under normal front lighting does not necessarily communicate how the same stone will behave when illuminated from behind.

For hospitality interiors, luxury retail, reception desks, feature walls and decorative architectural installations, this distinction can be commercially significant.

Block Dimensions and Geometry

Block geometry is one of the first practical considerations when purchasing onyx blocks.

The buyer should consider:

• Length
• Height
• Width
• Squareness
• Block integrity
• Surface condition
• Natural fractures
• Usable volume
• Expected slab dimensions

A larger block can potentially provide greater slab continuity, but size alone does not determine commercial value.

An oversized block with poor internal integrity may produce less useful material than a smaller but structurally sound block.

The key question is not simply:

How large is the block?

It is:

How much commercially usable finished stone can this block realistically produce?

That distinction is fundamental to block procurement.

Block Recovery and Yield

Yield is particularly important when buying onyx blocks.

The raw block represents the starting material. The buyer ultimately pays for a block that will be transformed into slabs or fabricated products.

During production, material can be lost through:

• Sawing
• Edge trimming
• Surface preparation
• Cracks
• Natural cavities
• Internal discontinuities
• Slab breakage
• Calibration
• Cutting defects
• Final sorting

A block with high visual appeal but poor recovery may have a very different effective cost per square meter from a more stable block with better yield.

For fabricators and project buyers, recovery should therefore be considered when comparing block prices.

A professional procurement assessment can examine the relationship between:

Block price → expected recovery → usable slab area → finished-product cost.

This is often more meaningful than comparing block prices alone.

Cutting Direction and Onyx Pattern

Cutting direction is one of the most important decisions in onyx processing.

The same block can produce substantially different visual effects depending on how it is oriented during sawing.

The production team may evaluate:

• Layer orientation
• Vein direction
• Dominant color bands
• Translucent layers
• Internal movement
• Desired slab pattern
• Bookmatch potential

The objective is to convert the three-dimensional geological structure of the block into the most commercially useful two-dimensional slab sequence.

For architectural projects, this decision can determine whether the finished surface appears calm, linear, symmetrical, dramatic or highly irregular.

Onyx Blocks for Bookmatched Slabs

Bookmatching is one of the most important high-value applications for selected onyx blocks.

When sequential slabs are opened and arranged as mirror-like pairs, the natural pattern can create a symmetrical composition.

This can be particularly effective for:

• Hotel reception walls
• Luxury residential interiors
• Feature fireplaces
• Lobby walls
• Bar counters
• Restaurant interiors
• Retail displays
• Decorative partitions
• Statement furniture
• Backlit feature panels

However, not every block is suitable for strong bookmatching.

The geological structure needs to produce a sufficiently coherent pattern across successive slabs.

Therefore, buyers seeking bookmatched onyx should communicate this requirement before block selection.

Color and Pattern Selection

Onyx is often purchased for its visual character rather than simply its base color.

A professional selection process should evaluate:

• Background color
• Vein density
• Vein direction
• Contrast
• Translucency
• Layering
• Mineral inclusions
• Pattern continuity
• Visual balance

A buyer may prefer either a relatively calm stone or a highly expressive material.

Neither approach is universally correct.

The appropriate choice depends on the architectural concept.

For a large hotel lobby, dramatic movement may be intentionally desired.

For a residential bathroom or furniture surface, a calmer pattern may be more appropriate.

The block should therefore be selected according to the finished design objective.

Natural Variation in Onyx Blocks

Natural variation is an inherent characteristic of natural stone.

A quarry block should not be treated like an engineered material manufactured from a perfectly homogeneous raw material.

Variation can occur between:

• Different blocks
• Different portions of the same block
• Sequential slabs
• Different extraction periods
• Different quarry zones

This is particularly important for onyx because visual movement is often one of the reasons the material is purchased.

The goal of professional procurement is not to eliminate all variation.

The goal is to define the acceptable variation.

This can be achieved through:

• Representative block photographs
• Multiple slab photographs
• Range samples
• Physical samples
• Production approvals
• Mockups
• Pre-shipment inspection

ASTM C1528/C1528M-26 is intended for professionals involved in designing, specifying, purchasing, fabricating and supplying natural stone and emphasizes selection of stone in relation to the application and the other components of the construction assembly.

Natural Features Versus Defects

Experienced stone buyers know that natural features and defects are not automatically the same thing.

An onyx block may contain geological characteristics that are part of the material’s natural identity.

These can include:

• Color transitions
• Mineral bands
• Small natural cavities
• Fine inclusions
• Veining
• Texture changes

Other conditions may be commercially unacceptable depending on the application:

• Significant structural fractures
• Unstable zones
• Excessive breakage
• Severe internal discontinuities
• Unsuitable dimensions
• Unacceptable surface damage

The distinction should be established according to the intended finished product.

A feature acceptable in a decorative wall may not be acceptable in a demanding fabricated component.

Resin, Filling and Reinforcement

Onyx can require repair, resin treatment or reinforcement during slab production depending on the material and the intended application.

The Natural Stone Institute’s technical material on marble and onyx includes discussion of physical and mechanical properties as well as common repairs and reinforcements.

The purpose of treatment can include:

• Stabilizing natural fractures
• Supporting fragile areas
• Improving slab integrity
• Filling cavities
• Enhancing surface continuity
• Preparing the slab for polishing

However, treatment should not be treated as a substitute for proper block selection.

A structurally unsuitable block cannot automatically be transformed into a high-quality commercial block merely through resin treatment.

The correct sequence is:

Select suitable block → evaluate structure → process appropriately → reinforce where required → inspect finished slabs.

Onyx Blocks and Slab Thickness

The intended finished application should influence thickness selection.

Different applications can require different thicknesses or construction methods.

For example, a decorative wall panel, countertop component and backlit architectural panel may have different structural and fabrication requirements.

The buyer should therefore specify:

• Target slab thickness
• Finished tolerance
• Calibration
• Reinforcement
• Backing requirements
• Edge treatment
• Fabrication method

The correct specification should be established with the fabricator or project team rather than assumed from a generic catalogue dimension.

Technical Evaluation of Onyx

Natural stone selection should be application-specific.

The relevant technical assessment can include:

• Density
• Water absorption
• Compressive strength
• Flexural properties
• Abrasion resistance
• Petrographic characteristics
• Soundness
• Dimensional properties

The precise testing program should depend on the intended use.

Natural Stone Institute’s technical resources identify dedicated standards, test methods, physical and mechanical properties, fabrication tolerances, repairs and reinforcements for marble and onyx.

This is particularly relevant for professional buyers because the commercial name “onyx” does not by itself establish that a material is suitable for every architectural application.

Onyx Blocks for Luxury Hospitality Projects

Hospitality projects are among the applications where the visual potential of onyx can become commercially valuable.

Potential applications include:

• Hotel lobbies
• Reception counters
• Feature walls
• Bar fronts
• Restaurants
• Spa interiors
• Elevator surrounds
• Decorative partitions
• Backlit panels
• Luxury retail environments

For such projects, the procurement process should start with the architectural intent.

The buyer may require a specific background, vein direction, translucency level and bookmatching potential.

This can make block selection a design decision rather than simply a purchasing decision.

Onyx Blocks for Fabricators

Fabricators purchasing raw onyx blocks need a different level of information from a buyer purchasing finished slabs.

A block buyer may need:

• Block dimensions
• Estimated weight
• Quarry/source information
• Block photographs
• Surface photographs
• Internal information where available
• Expected cutting direction
• Estimated slab potential
• Natural features
• Treatment expectations
• Loading information

The fabricator may then determine the optimal sawing strategy.

This is why high-quality block photographs should ideally show multiple faces and include dimensional references.

One front-facing photograph is rarely sufficient to evaluate a raw block commercially.

Onyx Blocks for International Importers

For an importer, the raw block represents both an opportunity and a responsibility.

Importing blocks allows the buyer or manufacturing partner to control more of the downstream processing.

Potential advantages include:

• Custom slab production
• Greater control over cutting direction
• Custom thickness
• Custom surface finishing
• Project-specific fabrication
• Bookmatching strategy
• Potentially improved control over slab selection

But block procurement also requires stronger technical evaluation than purchasing standard finished tiles.

The buyer needs to understand what is actually being purchased before committing to the shipment.

Onyx Blocks for Distributors

Distributors may purchase blocks to maintain access to distinctive materials that can later be processed according to market demand.

For distributors, important considerations include:

• Block consistency
• Marketability
• Color family
• Slab yield
• Finished slab demand
• Customer applications
• Production capability
• Replacement availability
• Source continuity

A distributor should avoid evaluating a block solely by its visual attractiveness.

The question is whether the material can be transformed into a commercially useful product for the distributor’s target market.

Inspection of Onyx Blocks Before Shipment

Pre-shipment inspection can be valuable for international block transactions.

Depending on the agreed scope, inspection may review:

• Block identity
• Dimensions
• Quantity
• Surface condition
• Visible fractures
• Visual characteristics
• Loading condition
• Photographic evidence
• Weight documentation
• Packaging and securing

Independent inspection can be incorporated when required by the buyer.

The inspection should be based on a clearly defined specification.

Without an agreed specification, even a detailed inspection can become subjective.

Photographs and Video in Onyx Block Procurement

Photography is particularly important for raw-block transactions.

A useful block presentation can include:

• Full block photographs
• Multiple faces
• Side views
• Close-ups of natural features
• Dimensions
• Markings
• Quarry or yard context
• Video showing the block from different angles

For translucent onyx, additional slab or sample information can be useful because the final visual effect cannot always be predicted from an exterior block photograph alone.

Digital inspection is valuable, but it should not be confused with physical inspection.

A photograph can communicate appearance.

It cannot independently establish every internal characteristic of a raw block.

Packaging and Loading Onyx Blocks for Export

Raw blocks require careful loading and securing because of their mass and geometry.

Export planning should consider:

• Block weight
• Dimensions
• Lifting points
• Loading equipment
• Securing method
• Container or vessel requirements
• Transport route
• Documentation
• Destination regulations

The commercial term should also be established clearly.

Depending on the transaction, the buyer and seller may negotiate EXW, FOB, CFR, CIF or another agreed delivery structure.

The exact commercial term determines which party is responsible for particular stages of transportation, cost and risk.

Pricing Onyx Blocks

There is no meaningful universal price for “onyx blocks.”

Block value depends on multiple variables.

These may include:

• Source
• Color
• Pattern
• Translucency
• Block size
• Geometry
• Structural integrity
• Internal fractures
• Expected recovery
• Bookmatching potential
• Market demand
• Processing potential
• Quantity
• Inspection requirements
• Loading and logistics
• Destination

A small block with exceptional pattern and high translucency may have a completely different commercial value from a larger block with less desirable movement.

Therefore, serious price comparisons should be based on comparable specifications.

How to Request an Onyx Block RFQ

A professional buyer can structure an inquiry around the following information:

Material: Onyx
Color: Specify preferred color family
Pattern: Calm / linear / dramatic / specified movement
Translucency: Required / preferred / not critical
Block dimensions: Required range
Quantity: Number of blocks or cubic meters
Intended use: Slabs / bookmatch / wall panels / countertops / decorative fabrication
Cutting direction: Required orientation if known
Inspection: Required / not required
Documentation: Technical and commercial documents required
Loading point: Agreed location
Delivery term: EXW / FOB / CFR / CIF or other agreed term
Destination: Port or final location

This gives the sourcing partner enough information to identify materially relevant options instead of sending unrelated photographs.

Why Block Selection Should Precede Slab Selection

When a project requires distinctive onyx, selecting the block first can provide better control over the final slab sequence.

The buyer can evaluate:

• Block geometry
• Geological structure
• Pattern direction
• Translucency
• Recovery potential
• Bookmatch potential

Then the production process can be designed around the intended result.

This approach is particularly useful for high-value architectural projects where several slabs need to work together as one visual composition.

For standard commercial projects, finished slab procurement may be more efficient.

For highly customized projects, block-level procurement can provide greater control.

Iranian Onyx Blocks

Iran is a significant source of natural stone, including commercially traded onyx varieties.

Iranian onyx is available in different visual families, and exact characteristics depend on the geological source and production zone.

International buyers should therefore avoid treating “Iranian onyx” as a single standardized material.

A professional inquiry should identify:

• Specific variety
• Color
• Visual characteristics
• Block dimensions
• Source information
• Cutting orientation
• Intended finished application
• Technical requirements

The advantage of working through a structured procurement process is that the buyer can compare material according to specification rather than according to commercial names alone.

ALPREY and Onyx Block Procurement

ALPREY operates as a specialized international procurement and trading house focused on connecting international buyers with Iranian natural-stone production sources.

For onyx blocks, the process can begin with the buyer’s finished-product objective.

A buyer may require raw blocks for:

• Premium slabs
• Bookmatched slabs
• Backlit panels
• Hotel interiors
• Luxury residences
• Retail interiors
• Decorative walls
• Custom architectural components

The sourcing process can then focus on identifying blocks whose dimensions, geological appearance, visual range and processing potential align with that requirement.

ALPREY does not present itself as a quarry owner or mining operator. Its role is procurement and commercial coordination, working through sourcing relationships and long-term off-take arrangements with Iranian production sources.

Where required, the procurement process can include specification development, production coordination, quality-control steps, photographic documentation and independent inspection.

The objective is to make the commercial process clearer before the material leaves the source.

Onyx Blocks and Long-Term Supply

For a one-time architectural project, a single block may be sufficient.

For distributors or recurring buyers, however, continuity becomes important.

A long-term supply program may define:

• Approved material
• Color family
• Pattern range
• Translucency expectations
• Block dimensions
• Quality criteria
• Inspection procedure
• Packaging
• Commercial terms
• Documentation

Natural stone will continue to vary because the geological resource itself varies.

The objective of long-term procurement is therefore not to promise artificial uniformity.

It is to establish a controlled commercial range.

Choosing Onyx Blocks by End Use

Different applications require different selection priorities.

For Backlit Walls

Prioritize:

• Translucency
• Pattern continuity
• Slab thickness
• Internal movement
• Bookmatching potential

For Countertops

Prioritize:

• Structural integrity
• Fabrication requirements
• Reinforcement
• Surface treatment
• Intended use conditions

For Hotel Feature Walls

Prioritize:

• Visual continuity
• Slab size
• Pattern
• Bookmatching
• Color range
• Production repeatability

For Decorative Furniture

Prioritize:

• Visual impact
• Slab yield
• Thickness
• Fabrication compatibility
• Edge processing

For Distributors

Prioritize:

• Marketable color
• Source continuity
• Recovery
• Production capacity
• Finished-product demand

The right block is therefore application-dependent.

The Difference Between a Beautiful Block and a Commercially Suitable Block

This distinction is at the heart of professional onyx procurement.

A beautiful block may have:

• Excellent color
• Dramatic veining
• Strong translucency

But if it has poor geometry, extensive internal fractures or low recovery, it may not be the right commercial choice.

A commercially suitable block balances:

Appearance + structure + dimensions + recovery + processing potential + application.

This is why professional buyers should evaluate onyx as a three-dimensional raw material rather than as a two-dimensional image.

Final Considerations for Onyx Block Buyers

Onyx blocks are not a standardized commodity in the same way as manufactured building products.

Their value comes from geological individuality.

The strongest procurement process recognizes that individuality while introducing enough structure to make the transaction commercially reliable.

A serious buyer should know:

• What the material is
• Where it comes from
• What the block dimensions are
• What visual characteristics are expected
• How the block should be sawn
• What the expected recovery may be
• Whether reinforcement may be required
• Whether the material is intended for backlighting
• What technical information is available
• How inspection will be performed
• How the block will be loaded and exported

The finished slab is only the visible result.

The real commercial decision begins with the block.

For international importers, distributors, fabricators and project buyers seeking Iranian onyx blocks, ALPREY provides a procurement-oriented connection between buyer specifications and Iranian natural-stone production sources.

The approach is deliberately straightforward:

Define the material.
Evaluate the block.
Control the process.
Inspect the shipment.
Respect the natural stone.

That is how raw onyx becomes a reliable starting point for premium architectural stone.