Dallasite Jasper Identification Guide
Identify Dallasite Jasper, a Vancouver Island green-black-white breccia, by its angular fragments, quartz-veined matrix, and silica hardness.
Read the full Dallasite Jasper encyclopedia entry →
What Dallasite Jasper Looks Like
Dallasite is a brecciated green volcanic rock from Vancouver Island, British Columbia, often sold as "Dallasite Jasper." It is a silicified breccia: angular fragments of dark green to black basaltic/volcanic material cemented and veined by white and pale-green quartz and chalcedony, sometimes with mossy or mottled patterns. Polished, it shows a striking green-black-and-white patchwork.
- Color: forest green and black fragments in white-to-cream silica veining
- Luster: waxy to vitreous when polished
- Transparency: opaque (green) with translucent white silica veins
- Texture: brecciated/fragmental, angular clasts in a silica matrix
Step-by-Step Field-ID Checklist
- Look for breccia texture. Angular green/black fragments cemented by lighter quartz veining is the signature.
- Check hardness. The silicified material scratches glass (Mohs ~6.5-7).
- Wet or polish a surface. This brings out the green-white contrast and any moss-like detail.
- Confirm opacity of the green parts. Green fragments stay opaque; veins may be translucent.
- Acid test. No fizz (silica-rich, not carbonate).
Key Diagnostic Tests
- Mohs hardness: ~6.5-7 for silicified portions; scratches glass.
- Streak: white to pale greenish.
- Fracture: conchoidal to uneven; tough due to silica cement.
- Acid: inert to dilute HCl.
- Density: ~2.6-2.8 g/cm3.
Common Look-Alikes and How to Tell Them Apart
- Other green jaspers (e.g., green/kambaba): Dallasite is specifically a breccia with angular green clasts and white quartz veins, not orbicular or uniformly banded.
- Unakite: Pink and green (epidote + feldspar) granitic look; dallasite lacks the salmon-pink feldspar and is a silicified breccia.
- Bloodstone: Dark green chalcedony with red spots, not the angular green-black-white breccia of dallasite.
- Serpentine: Softer (knife scratches it) and waxier/greasier; dallasite is harder and fragmental.
- Vancouverite: A related but distinct Vancouver Island green-and-pink stone; dallasite is green-black-white.
Where It Is Found
Dallasite occurs on Vancouver Island, British Columbia, Canada, classically along beaches and rivers (named for Dallas Road in Victoria). It is collected as beach cobbles and from local outcrops of altered volcanic rock.
Frequently asked questions
How can you tell if it's real Dallasite Jasper?
Look for the brecciated texture: angular dark-green to black volcanic fragments cemented by white-to-pale-green quartz and chalcedony veining. Confirm it is silicified by testing hardness (scratches glass, Mohs ~6.5-7) and that it does not fizz in acid.
What does Dallasite Jasper look like?
It looks like a green-black-and-white patchwork stone, with angular forest-green and black fragments held in a network of white quartz veins, taking a waxy-to-glassy polish.
Where is Dallasite Jasper found?
On Vancouver Island, British Columbia, Canada, classically along beaches and rivers near Victoria, collected as cobbles and from altered volcanic outcrops.
Dallasite vs unakite: how do I tell them apart?
Unakite is a pink-and-green granitic rock with salmon feldspar and green epidote, while dallasite is a green-black-and-white silicified breccia. The pink coloring of unakite is the easy distinguishing feature.
Is Dallasite a jasper or a breccia?
It is a silicified volcanic breccia that is marketed as a jasper because of its hardness, opacity, and polish. Technically it is a breccia of green volcanic clasts in a quartz/chalcedony matrix.
Dallasite Jasper identified by the community
Recent Dallasite Jasper specimens identified with Rock Identifier.
