Method of identification of natural building stones
1975 Edition

Overview of IS 1123 Scope & Essential Specifications

Scope (Clause 3.2):

• Identification techniques for building stones based on physical and engineering attributes.
• Categorization of stones into Igneous, Sedimentary, and Metamorphic groups.
• Reference to Table 1 for properties and characteristics.

Representative Table: Stone Characteristics (Excerpt from Table 1)

Important Notes:

• Stones intended for structural use should be free from defects, joints, and fractures.
• Engineering properties such as compressive and tensile strength, porosity, and elasticity modulus inform suitability.
• Refer to Table 1 when selecting stones for specific project needs.

flowchart LR
    A[Determine Rock Type] --> B{Rock Classification}
    B -->|Igneous| C[Granite / Basalt / Syenite]
    B -->|Sedimentary| D[Sandstone / Limestone]
    B -->|Metamorphic| E[Schist / Quartzite]
    C --> F[Evaluate Engineering Properties]
    D --> F
    E --> F
    F --> G[Choose Stone Based on Strength & Application]

For comprehensive design, consult IS 1123 Table 1 and follow sample identification and reporting procedures (Clause 4.1).

IS 1123: Procedures for Selecting Natural Stone Samples

Key Parameters:

• Source of Sample: Fresh, unweathered rock from quarry ledge or natural outcrop.
• Minimum Sample Weight: At least 25 kg from each distinct stratum.
• Sampling Process:
  • Examine quarry face for differences in color, texture, and structure.
  • Collect separate specimens from each visually distinct layer.
  • Exclude stones damaged by blasting, wedges, or heat treatment.

Summary Table:

Notes:

• Sufficient sample size allows preparation of all necessary test specimens.
• Sampling must represent all visible variations to maintain stone grade consistency.

flowchart TD
    A[Examine Quarry Face] --> B{Are There Variations?}
    B -- Yes --> C[Collect ≥ 25 kg Sample per Variation]
    B -- No --> D[Collect ≥ 25 kg Sample]
    C & D --> E[Exclude Damaged Stones]
    E --> F[Prepare Test Samples]

This procedure ensures representative and undamaged samples for reliable identification and testing.

IS 1123: Steps for Identifying Natural Building Stones

1. Reporting Details (Clause 4.1)

• Include sample collection date, sample identification, and stone type.

2. Stone Characteristics (Table 1, Clause 3.2)

3. Typical Stone Varieties & Applications

• Granite: High strength, used for bridges, dams, monuments.
• Basalt: Dense, used for heavy construction and pavements.
• Sandstone: Used in masonry, dams, and decorative stones.
• Syenite, Trachyte, Andesite: Employed as dimension stones or aggregates.

4. Identification Summary

• Evaluate colour, texture, and mineral makeup.
• Test physical parameters: specific gravity, strength, and porosity.
• Inspect for defects such as joints, fractures affecting usability.

Sample Granite Properties Overview

IS 1123 - Guidelines for Stone Identification Reporting

Reporting Essentials (Clause 4.1)

• Reports should specify:
  • Sample collection date
  • Sample identification details
  • Stone classification (refer to Table 1)

Table 1: Stone Characteristics & Engineering Data (Clause 3.2)

Usage and Availability Notes

• Granites and basalts are preferred for heavy engineering structures.
• Sedimentary stones like sandstone are commonly used in masonry and ornamental work.
• Metamorphic stones such as slate are suitable for roofing and tiles.

Reporting Workflow Diagram

flowchart TD
    A[Sample Collection] --> B[Record Date and ID]
    B --> C[Determine Stone Type]
    C --> D[Consult Table 1 for Properties]
    D --> E[Prepare Report]
    E --> F[Submit to BIS or Client]

Note: Always utilize IS 1123 Table 1 for detailed classification and property data during reporting to ensure clarity and traceability.

IS 1123: Key Physical and Engineering Properties of Stones

Common Stones and Their Applications:

• Granite: Light to pink, quartz and feldspar rich; high strength; used in bridges, monuments, pavements.
• Basalt (Deccan Trap): Dark grey/black, medium-grained; used in heavy constructions and road metal.
• Sandstone: Stratified, quartz-dominant; used in masonry, dams, and ornamental stone.
• Slate: Fine-grained, fissile; used for roofing and tiles.
• Khondalite & Schists: Used in blocks and slabs, though more prone to weathering.

Notes:

• Structural stones must be free from defects such as cracks and joints.
• Porosity and abrasion resistance directly influence longevity.
• Identification involves color, texture, mineral content, and engineering parameters.

flowchart LR
    A[Building Stones] --> B[Physical Properties]
    B --> C[Specific Gravity]
    B --> D[Strength: Compressive, Tensile, Shear]
    B --> E[Porosity & Abrasion Resistance]
    B --> F[Modulus of Elasticity]
    A --> G[Applications]
    G --> H[Structural: Bridges, Dams]
    G --> I[Decorative: Monuments, Tiles]

Reference: IS 1123 Table 1, Clause 3.2 for comprehensive stone characteristics.

Classification Framework for Natural Building Stones Under IS 1123

This standard categorizes natural building stones primarily according to their rock type, physical characteristics, and engineering qualities.

Principal Rock Categories & Attributes (Table 1, Clause 3.2)

IS 1123: Essential Physical and Mechanical Characteristics of Building Stones

Summary of Key Properties (Table 1, Clause 3.2):

Common Stones and Their Applications:

• Granite: Exhibits high strength (2 × 10⁵ to 6 × 10⁵ kg/cm²), suitable for heavy construction, pavements, and monuments.
• Basalt: Medium to high strength (1500-3000 kg/cm²), ideal for bridge piers and river embankments.
• Sandstone: Moderate strength (200-1700 kg/cm²), used in masonry and dam construction.
• Slate: Low to medium strength (1000-2000 kg/cm²), preferred for roofing and tile production.

Additional Information:

• Strength and other properties depend on mineral content and texture.
• Porosity impacts durability; lower porosity enhances weather resistance.
• Joints and cracks reduce effective strength and functional performance.

Elasticity Modulus Formula:

[ E = \frac{\sigma}{\epsilon} ] Where:

• ( \sigma ) = applied stress (kg/cm²)
• ( \epsilon ) = strain (unitless)

Diagram: Relationship of Rock Properties and Usage

graph TD
    A[Building Stones] --> B[Igneous Rocks]
    A --> C[Sedimentary Rocks]
    B --> D[Granite]
    B --> E[Basalt]
    C --> F[Sandstone]
    C --> G[Slate]

Applications and Usage Guidelines According to IS 1123

Sampling and Inspection (Clauses 2.2.1 & 2.2.2)

• Sample Requirements: Minimum 25 kg from each stratum exhibiting distinct color, texture, or structure.
• Inspection Focus: Examine quarry faces and field stones for variations, joints, fractures, and imperfections.
• Rejection Criteria: Stones affected by blasting, heating, or containing cracks and joints unsuitable for homogeneous blocks.

Physical and Mechanical Properties Overview (Table 1 Highlights)

Important Considerations

• Stones must be free from defects to ensure long-term durability.
• Porosity affects weather resistance; lower porosity is preferred for structural applications.

Inspection Protocols for Quarry and Field Stones as per IS 1123

Relevant Clauses:

• Clause 2.2.1 (Quarry Stones):

  • Survey quarry face for stratigraphic variations in color, texture, and structure.
  • Collect samples weighing at least 25 kg from each distinct stratum.
  • Exclude stones damaged by blasting, wedges, or heat exposure.

• Clause 2.2.2 (Field Stones & Boulders):

  • Conduct thorough area inspection.
  • Record stone types and conditions.
  • Collect separate samples for each visually distinct category.

• Clause 4.1 (Reporting):

  • Document sample date, identification, and stone type.

Extract from Table 1: Stone Properties (Clause 3.2)

Inspection Summary:

1. Visual Examination: Identify strata differences in color, texture, and structure.
2. Sampling: Quarry samples ≥ 25 kg per stratum; field samples per stone class.
3. Exclusion: Reject stones with damage or deterioration.
4. Reporting: Record sample details including collection date and stone classification.

IS 1123: Essential Annexures, Tables, and Key Specifications

1. Table 1: Building Stone Characteristics (Clause 3.2)

2. Stone Varieties and Their Applications

• Granite: High strength, used in dams, bridges, and monuments.
• Basalt (Deccan Trap): Dense stone suitable for heavy structural uses.
• Sandstone: Employed in masonry, dams, and ornamental stonework.
• Trachyte & Andesite: Used as dimension stones and for decorative purposes.

3. Reporting Protocol (Clause 4.1)

• Include sample collection date.
• Provide sample identification.
• Specify stone type.

4. Identification Approach

• Petrographic examination.
• Mineralogical composition analysis.
• Texture and structural evaluation.

Example: Granite Compressive Strength Classification

Stone Identification Workflow

flowchart TD
    A[Sample Collection] --> B[Physical Examination]
    B --> C[Petrographic Analysis]
    C --> D[Mineralogical Composition]
    D --> E[Classification and Reporting]

Note: The values provided are indicative; always refer to the latest edition of IS 1123 for precise data.