How to identify Bloodstone

To correctly identify Bloodstone (Heliotrope (variety of Chalcedony)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Dark green body color with distinct red, reddish-brown, or yellow spots/streaks.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Waxy to vitreous.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to slightly granular, cryptocrystalline.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Massive, botryoidal, or stalactitic aggregates; individual crystals are microscopic.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None (cryptocrystalline quartz).

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Found in amygdaloidal cavities in volcanic rocks (e.g., basalts, andesites), alluvial deposits, and as secondary deposits in some metamorphic rocks. It forms from low-temperature hydrothermal solutions.

Key Facts

Hardness

6.5-7 on Mohs scale

Specific Gravity

2.58-2.64

Crystal System

Trigonal (cryptocrystalline aggregates)

Color

Dark green with red, reddish-brown, or yellow spots/streaks

Luster

Waxy to vitreous

Transparency

Opaque to translucent

Fracture

Conchoidal to uneven

Cleavage

None

Composition

Silicon dioxide (SiO2) with inclusions of chlorite, hornblende, and hematite

Physical characteristics

• Crystal Habit: Massive, cryptocrystalline aggregates; individual crystals are microscopic and fibrous.
• Cleavage Type: None, due to its cryptocrystalline structure.
• Fracture Type: Conchoidal to uneven, typical of quartz varieties.
• Tenacity: Brittle.
• Luster Type: Waxy to vitreous, sometimes dull on unpolished surfaces.

Explore Bloodstone