Hematoid Quartz: Iron Oxide Inside Quartz
Hematoid quartz explained: how iron oxide colours quartz from within, origin differences, name decoder, and a 5-point grading guide.
In this field note
Cut open a piece of hematoid quartz and the story of its formation is right there on the cross-section: translucent quartz interrupted by clouds, wisps, and fracture lines of red to brown pigment. That pigment is iron oxide, the most abundant colouring agent in the Earth’s crust, trapped inside one of the most common minerals on the planet. The combination should feel ordinary. It does not.
The grading notes further down come from the lot records BE. Crystal Jewellery keeps for its own hematoid material.Hematoid quartz is common. What makes it interesting is legibility. Every strand records a geological process you can see with the naked eye: where iron-rich fluid entered the quartz, and which cracks or surfaces it followed. The sections below cover the chemistry, the naming mess, major sources, and a practical grading framework for buyers.
What makes hematoid quartz red
The red to brown colouration in hematoid quartz comes from microscopic particles of iron oxide held inside the quartz. The particles are separate mineral grains; the SiO₂ lattice around them stays colourless. “Iron oxide” is a family of compounds, and the specific species present determines the exact hue.
| Iron oxide species | Chemical formula | Colour contribution | Common occurrence in quartz |
|---|---|---|---|
| Hematite | Fe₂O₃ | Red to reddish brown | The phase most often identified in hematoid quartz; finely dispersed platelets or films along fractures |
| Magnetite | Fe₃O₄ | Black to dark grey | Less common in quartz; occasionally found as discrete micro-inclusions |
| Goethite | FeOOH | Yellow to brownish orange | Often accompanies hematite; responsible for warmer, golden-brown tones |
| Lepidocrocite | γ-FeOOH | Reddish orange to orange | Often claimed for red flakes in “strawberry” quartz; Mindat notes that most material sold this way is hematite, and appearance alone cannot identify it |
Hematite is the iron oxide most often identified in hematoid quartz. The particles are typically sub-micrometre in size. Individually they are too small to see. Together they scatter enough light to produce visible colour. In some hematoid quartz, including the Brazilian material BE. uses, the iron-oxide material sits along fractures, where iron-rich fluid seeped in after the quartz had formed. In some other red quartz, hematite settled on a growth face and was overgrown, leaving a red phantom outline. The high contrast between transparent quartz and opaque red hematite makes these inclusions unusually photogenic.
The iron itself originates from iron-bearing fluids circulating through the host rock, during growth or later through cracks in the crystal. A crystal with several iron-stained fractures records several pulses of iron-rich solution. For a broader discussion of why iron produces different colours in different mineral hosts, see our guide to why iron looks different colours in crystals.
Hematoid vs strawberry vs fire quartz: the name decoder
Few gemstones suffer from as much naming confusion as this one. The same stone, or closely related stones, circulate under multiple trade names. Some overlap. Some contradict each other. Here is what each name typically refers to and where the boundaries blur.
| Trade name | Typical inclusion | Appearance | Notes |
|---|---|---|---|
| Hematoid quartz | Iron oxides, often hematite (Fe₂O₃) | Red to brown clouds, wisps, or fracture-bound films in clear-to-milky quartz | The oldest of these names: Haüy wrote “quartz hématoïde” in 1796. “Hématoïde” means blood-like, so the name describes the colour and does not prove hematite is present |
| Fire quartz | Iron oxides, often hematite | Overlaps with hematoid quartz | A trade name used for much of the same material; “fire” refers to the red colour and promises no optical effect |
| Strawberry quartz | Sold as lepidocrocite or goethite; tested material often proves to be hematite | Pink to pinkish red, often more uniformly distributed than hematoid | Loosely applied; some vendors use it for any pinkish quartz with inclusions |
| Red phantom quartz | Hematite along growth surfaces | Distinct red “ghost” outline visible inside the quartz crystal | Describes a growth feature (phantom) and names no mineral species |
| Ferruginous quartz | Any iron oxide / hydroxide | Variable: red, brown or yellow depending on iron species | A catch-all geological term; technically the broadest category |
The practical takeaway: hematoid quartz and fire quartz overlap so heavily that most sellers use them for the same material, and neither name is a mineral species. Strawberry quartz may or may not be the same thing depending on the vendor and the actual inclusion species present. If you care about precision, look for the inclusion mineral itself, since the commercial name does not settle it. For a broader look at iron-bearing red and orange gemstones, our guide to red and orange crystals covers the spectrum.
Origin fingerprints
The hematoid material in the linked BE. Koi bracelet comes from Brazil. Its iron-rich material follows fine internal fractures. A country name does not establish the texture, mineral phases or quality of every piece from that country.
| Source | Linked material | Recorded structure | Scope |
|---|---|---|---|
| Brazil | BE. Koi Hematoid Quartz Bracelet | Iron-rich material along fine internal fractures | This lot; not all Brazilian quartz |
Read the texture that is actually visible: the distribution of iron-rich material, the quartz between coloured areas and how the beads sit together in a strand. Origin remains a separate recorded fact.
Reading a hematoid quartz strand
BE. grades hematoid quartz with BE. Crystal 4T™: Transparency, Tone, Texture and Treasure. The observations below describe a strand's appearance. They are not an additional grading system.
For the finished piece, compare one double-strand bracelet with two separate bracelets before deciding how you want to wear them.
- Inclusion visibility.Look at how clearly the iron-rich clouds, wisps or fracture lines can be seen inside the quartz. Compare the coloured areas with the clear spaces around them under the same light.
- Colour saturation.Describe the red to red-brown tone and how it varies between beads. In BE. Crystal 4T™, Tone considers the colour of each bead and the consistency of the whole strand.
- Quartz clarity.Look through the quartz between the inclusions. Clearer areas make the internal red material easier to distinguish; more clouded areas give it a softer appearance.
- Inclusion definition.Follow the red lines or films through the bead and note whether their edges are sharp or diffuse. Both are visible textures; the pattern alone does not establish a rarity grade.
- Strand consistency.Compare hue, inclusion density and host clarity across the strand. Those observations show how the beads relate to one another and support a description of the full strand.
Care, durability, and grading
Hardness and wear
The quartz host has a hardness of about Mohs 7; fractured beads still need care. Most of the iron oxide sits inside the quartz, protected from skin and air. Where a filled fracture reaches the surface of a bead, treat that bead as you would any fractured stone and avoid knocks.
- Water exposure. Brief contact with water during hand-washing is harmless. Prolonged submersion is unnecessary but unlikely to cause damage. Remove the bracelet before swimming or showering, since repeated soaking wears the stringing faster.
- Sunlight. Iron-oxide pigments such as hematite are among the most lightfast colourants known, far more stable than organic dyes. Natural, untreated hematoid quartz keeps its colour in normal outdoor wear; a dyed crackle-quartz imitation may not.
- Cleaning. Warm water with a drop of mild soap and a soft brush is sufficient. Rinse thoroughly, pat dry. Skip ultrasonic and steam cleaners: the vibration and heat can stress fractured beads, and routine care does not need them.
How BE. grades hematoid quartz
The linked Koi Hematoid Quartz Bracelet has recorded Transparency, Tone, Texture and Treasure readings. Its Stone Origin Record identifies the lot, Brazil as origin and untreated status. The product record is the source for those lot-specific details.
The Koi Hematoid Quartz Bracelet has a Stone Origin Record stating its material, country of origin and treatment status.
Frequently asked questions
Q1. What is hematoid quartz?
Hematoid quartz is macrocrystalline quartz (SiO₂) that contains iron-oxide inclusions, most often identified as hematite (Fe₂O₃). The iron oxide gives the quartz a red to reddish-brown colour, often appearing as clouds, wisps, or films along fractures inside the crystal. The name is a trade description and the mineral is quartz; the material occurs naturally in many localities worldwide.
Q2. Is hematoid quartz the same as fire quartz?
The two names overlap heavily. Fire quartz is a trade name that most sellers use for the same red, iron-included quartz. “Fire” refers to the red colour; the material shows no optical fire effect. Neither name is a mineral species, and neither tells you which iron mineral a given stone contains.
Q3. What makes hematoid quartz red?
The red colour comes from very fine particles of iron oxide, most often hematite (Fe₂O₃), held inside the quartz as separate grains or as films along fractures. Hematite is the same iron oxide responsible for the red colour of rust, red soil, and ochre pigment. The denser and more finely dispersed the particles, the deeper and more vivid the red.
Q4. Is hematoid quartz natural or treated?
Hematoid quartz is a natural material. The iron oxide inclusions form when iron-bearing fluids enter the quartz, during growth or later along fractures. Dyed crackled quartz is sold as an imitation: the dye collects in cracks that reach the surface, which magnification often shows, though only laboratory testing proves it. The hematoid quartz in BE. bracelets comes from Brazil and is untreated.
Q5. What is the difference between hematoid quartz and strawberry quartz?
The distinction is blurred in the trade. Strawberry quartz is usually sold as quartz with lepidocrocite (γ-FeOOH) or goethite (FeOOH) inclusions, giving a pinker, more evenly spread colour, though Mindat notes that most red flakes sold as lepidocrocite turn out to be hematite. In practice, many vendors use “strawberry quartz” loosely for any pinkish or reddish included quartz regardless of the actual inclusion species. If precision matters, look for the inclusion mineral itself.
References
Field Notes.
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