Slate knowledge

Specify cleavage, orientation and intended use.

The 10 Slate routes are commercial names. ASTM C629 dimension slate explicitly excludes roofing slate; roofing requires separate ASTM C406 or applicable IS 6250 evidence and specialist roof design.

Browse slate Build project request

live routes

buying programmes

name collisions

roofing grades verified

Identity control

Dimension slate is not automatic roofing slate.

Confirm geological slate, cleavage, mineral ribbons and orientation. Select the use-specific standard before requesting evidence or making a suitability claim.

Cleavage

Record face/back, splitting plane, thickness, loose flakes and along/across-grain test orientation.

Cross-family names

Copper, Silver Grey and Ocean Green remain family-qualified identities with separate media, sources and inventory.

Roofing

Require verified roofing grade, breaking load, absorption/softening evidence, headlap, fastening and roof design.

Buying programmes

Three approval paths cover every Slate route.

These appearance groups organize selection without creating geological or roofing grades.

4 routes

Dark & grey slate

Compare cleavage, shade, grain, mineral ribbons, thickness, edge response, oxidation and wet appearance.

Approve current split/calibrated range and intended orientation; colour or locality does not establish roofing grade.

Deoli Green Kund Black Silver Grey ⚠Himachal Black

4 routes

Multicolour & rustic slate

Compare iron/mineral colour spread, surface relief, sequence, oxidation, flaking and crate mix.

Approve dry and wet range panels plus acceptable colour proportions; one tile cannot represent a multicolour programme.

Copper ⚠Multicolor Autumn Rustic

2 routes

Green & peacock slate

Compare green undertone, iridescent/mineral colour, cleavage, shade range, surface texture and weathering.

Resolve cross-family naming, geological identity and current lot before approving colour, source or application.

Peacock Ocean Green ⚠

Evidence matrix

Keep results use- and orientation-specific.

Dimension and roofing results are not interchangeable. Use the licensed current standard and exact lot.

Commercial identity

commercial-identity

Approved name, aliases and family-qualified substitutions; shared colour names must not merge across Slate, Quartzite or other families.

Geological identity

petrographic-identity

Fine-grained metamorphic slate, cleavage, mineralogy, ribbons, alteration and use-relevant constituents supported where required.

Dimension vs roofing

use-standard

ASTM C629 dimension-slate scope or ASTM C406/IS 6250 roofing scope explicitly selected; never inferred from catalogue family.

Source & lot

origin-and-lot

Country, region, quarry/program and bench/lot evidence at the precision claimed.

Cleavage & grain

cleavage-orientation

Splitting plane, face/back, along/across grain test orientation and installation orientation.

Dimensions & calibration

dimensions

Length/width, thickness range, calibration, relief, flatness, squareness, edge and hole/fixing geometry.

Absorption

absorption

Lot-linked result under the selected dimension or roofing method and specimen condition.

Strength by use

mor-or-breaking-load

Dimension-slate MOR along/across grain or roofing breaking-load evidence kept use- and method-specific.

Abrasion & slip

abrasion-slip

Exact-finish traffic and wet/dry evidence for floors, paving, steps or wet areas.

Acid & weathering

acid-weathering

Applicable acid resistance, softening, freeze–thaw, wetting/drying, oxidation and mineral-ribbon review.

Fixing & assembly

fixing-system

Roof headlap/fastening or wall/paving fixing, substrate, drainage, joints and replacement strategy.

Cleaning & maintenance

maintenance

Mock-up cleaning, sealer if used, colour change, efflorescence and long-term access/replacement plan.

Finish control

Surface and calibration must be measured.

Natural cleft is not a dimensional tolerance.

Natural cleft

Control relief, loose flakes, thickness, lippage, wet slip, cleanability and face orientation.

Calibrated natural cleft

State face relief and calibrated-back tolerance separately; confirm adhesive bed and floor flatness.

Honed

Confirm the slate hones uniformly and approve shade, scratches, wet slip, oxidation and sealing.

Brushed

Approve texture, loose mineral response, cleaning, edges and lot consistency.

Application control

Use determines the evidence path.

Floor, façade, wet-area and roof assemblies need different controls.

Interior floors & walls

Conditional

Cleavage integrity, calibration, lippage, abrasion/slip, substrate, fixing, joints and maintenance.

Exterior paving & steps

Engineering review

Wet slip, strength orientation, thickness, saturation, freeze–thaw/deicing, drainage and flaking/weathering.

Wall cladding

Engineering review

Panel geometry, cleavage orientation, flexure/anchors, wind/seismic loads, joints and water management.

Roof shingles

Specialist roofing review

ASTM C406/IS 6250 scope, verified roofing grade, size/thickness, breaking load, absorption/softening, headlap, fastening and roof design.

Wet areas

Engineering review

Exact-finish wet slip, cleavage/flaking, absorption, drainage, chemicals, fixing and cleaning.

RFQ checklist

Make use, orientation and fixing explicit.

Send identical identity, source, dimensional, evidence and assembly requirements to every source.

1Commercial name, family and cross-family substitutions
2Dimension-slate or roofing-slate scope
3Petrographic identity, quarry/program and lot
4Application, destination, exposure and governing standard
5Size, thickness range, calibration, relief and edge
6Cleavage/grain, face/back and test orientation
7Finish plus approved dry/wet range and crate mix
8Use-specific test methods and acceptance criteria
9Fixing/roofing design, inspection and replacement
10Packing, labels, Incoterm, port and handling constraints

Blocked shortcuts

Slate family treated as roofing approval.
Dimension MOR substituted for roofing breaking load.
Strength without grain orientation.
Shared colour name merged across families.
Natural cleft without relief limits.
Exterior use without weathering evidence.

Specify slate by identity, cleavage, lot and use.

Build project request

Harobal Stones

Luxury Architectural Crafts

Slate knowledge

Specify cleavage, orientation and intended use.

The 10 Slate routes are commercial names. ASTM C629 dimension slate explicitly excludes roofing slate; roofing requires separate ASTM C406 or applicable IS 6250 evidence and specialist roof design.

Browse slate Build project request

live routes

buying programmes

name collisions

roofing grades verified

Identity control

Dimension slate is not automatic roofing slate.

Confirm geological slate, cleavage, mineral ribbons and orientation. Select the use-specific standard before requesting evidence or making a suitability claim.

Cleavage

Record face/back, splitting plane, thickness, loose flakes and along/across-grain test orientation.

Cross-family names

Copper, Silver Grey and Ocean Green remain family-qualified identities with separate media, sources and inventory.

Roofing

Require verified roofing grade, breaking load, absorption/softening evidence, headlap, fastening and roof design.

Buying programmes

Three approval paths cover every Slate route.

These appearance groups organize selection without creating geological or roofing grades.

4 routes

Dark & grey slate

Compare cleavage, shade, grain, mineral ribbons, thickness, edge response, oxidation and wet appearance.

Approve current split/calibrated range and intended orientation; colour or locality does not establish roofing grade.

Deoli Green Kund Black Silver Grey ⚠Himachal Black

4 routes

Multicolour & rustic slate

Compare iron/mineral colour spread, surface relief, sequence, oxidation, flaking and crate mix.

Approve dry and wet range panels plus acceptable colour proportions; one tile cannot represent a multicolour programme.

Copper ⚠Multicolor Autumn Rustic

2 routes

Green & peacock slate

Compare green undertone, iridescent/mineral colour, cleavage, shade range, surface texture and weathering.

Resolve cross-family naming, geological identity and current lot before approving colour, source or application.

Peacock Ocean Green ⚠

Evidence matrix

Keep results use- and orientation-specific.

Dimension and roofing results are not interchangeable. Use the licensed current standard and exact lot.

Commercial identity

commercial-identity

Approved name, aliases and family-qualified substitutions; shared colour names must not merge across Slate, Quartzite or other families.

Geological identity

petrographic-identity

Fine-grained metamorphic slate, cleavage, mineralogy, ribbons, alteration and use-relevant constituents supported where required.

Dimension vs roofing

use-standard

ASTM C629 dimension-slate scope or ASTM C406/IS 6250 roofing scope explicitly selected; never inferred from catalogue family.

Source & lot

origin-and-lot

Country, region, quarry/program and bench/lot evidence at the precision claimed.

Cleavage & grain

cleavage-orientation

Splitting plane, face/back, along/across grain test orientation and installation orientation.

Dimensions & calibration

dimensions

Length/width, thickness range, calibration, relief, flatness, squareness, edge and hole/fixing geometry.

Absorption

absorption

Lot-linked result under the selected dimension or roofing method and specimen condition.

Strength by use

mor-or-breaking-load

Dimension-slate MOR along/across grain or roofing breaking-load evidence kept use- and method-specific.

Abrasion & slip

abrasion-slip

Exact-finish traffic and wet/dry evidence for floors, paving, steps or wet areas.

Acid & weathering

acid-weathering

Applicable acid resistance, softening, freeze–thaw, wetting/drying, oxidation and mineral-ribbon review.

Fixing & assembly

fixing-system

Roof headlap/fastening or wall/paving fixing, substrate, drainage, joints and replacement strategy.

Cleaning & maintenance

maintenance

Mock-up cleaning, sealer if used, colour change, efflorescence and long-term access/replacement plan.

Finish control

Surface and calibration must be measured.

Natural cleft is not a dimensional tolerance.

Natural cleft

Control relief, loose flakes, thickness, lippage, wet slip, cleanability and face orientation.

Calibrated natural cleft

State face relief and calibrated-back tolerance separately; confirm adhesive bed and floor flatness.

Honed

Confirm the slate hones uniformly and approve shade, scratches, wet slip, oxidation and sealing.

Brushed

Approve texture, loose mineral response, cleaning, edges and lot consistency.

Application control

Use determines the evidence path.

Floor, façade, wet-area and roof assemblies need different controls.

Interior floors & walls

Conditional

Cleavage integrity, calibration, lippage, abrasion/slip, substrate, fixing, joints and maintenance.

Exterior paving & steps

Engineering review

Wet slip, strength orientation, thickness, saturation, freeze–thaw/deicing, drainage and flaking/weathering.

Wall cladding

Engineering review

Panel geometry, cleavage orientation, flexure/anchors, wind/seismic loads, joints and water management.

Roof shingles

Specialist roofing review

ASTM C406/IS 6250 scope, verified roofing grade, size/thickness, breaking load, absorption/softening, headlap, fastening and roof design.

Wet areas

Engineering review

Exact-finish wet slip, cleavage/flaking, absorption, drainage, chemicals, fixing and cleaning.

RFQ checklist

Make use, orientation and fixing explicit.

Send identical identity, source, dimensional, evidence and assembly requirements to every source.

1Commercial name, family and cross-family substitutions
2Dimension-slate or roofing-slate scope
3Petrographic identity, quarry/program and lot
4Application, destination, exposure and governing standard
5Size, thickness range, calibration, relief and edge
6Cleavage/grain, face/back and test orientation
7Finish plus approved dry/wet range and crate mix
8Use-specific test methods and acceptance criteria
9Fixing/roofing design, inspection and replacement
10Packing, labels, Incoterm, port and handling constraints

Blocked shortcuts

Slate family treated as roofing approval.
Dimension MOR substituted for roofing breaking load.
Strength without grain orientation.
Shared colour name merged across families.
Natural cleft without relief limits.
Exterior use without weathering evidence.

Specify slate by identity, cleavage, lot and use.

Build project request