The Lovenhall RegistryThe LovenhallRegistry
House · VI№ VI

Lovenhall Stone

The room where the house keeps its instrument for what came out of the ground — a rock, mineral, crystal or fossil named from a photograph, with the three field tests that actually settle it beside the reading. Indicative throughout; never a verdict.

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House of the Ground

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Mohs Hardness TesterSpecific Gravity Calculator
Lovenhall Stone Identifier№ VI · iPhone & iPad
Nº I · The Instrument

Stone Identifier

Photograph a stone and the instrument names what it appears to be — rock, mineral, crystal or fossil — with its properties, how common it is, and a rough idea of what a find like it is worth. For anyone who picks things up and wonders.

Names rocks, minerals, crystals and fossils
Properties, hardness and rarity in plain language
A rough idea of what a find is worth
Open the Stone Identifier

Free on iPhone & iPad. Any figure it gives is an estimate, not an appraisal.

What it reads, and what it cannot
Nº II · In the Hand

Three moves, and you have a figure

You photograph it. The instrument reads it. You know where you stand.

I

You photograph it

One photograph. Nothing to fill in, nothing to send away.

II

It reads what it sees

The reading happens there and then, on the phone.

III

You have a figure to work from

A range, in seconds — enough to know where you stand.

Nº III · How a Mineral Is Read

Six properties, and not one of them is colour

Hardness, streak and density identify most of what anyone finds, and a camera can measure none of the three.

Hardness

Mohs 1 – 10

Fingernail 2.5 · Copper coin 3.5 · Knife & glass 5.5 · Steel file 6.5

Streak

Powder, not surface

Red-brown hematite · Greenish-black pyrite · Yellow gold · White quartz

Specific gravity

Weight for size

Amber 1.05 · Opal 2.1 · Quartz 2.65 · Pyrite 5.0 · Gold 19.3

Cleavage & fracture

How it breaks

Quartz: none · Calcite: three ways · Fluorite: four · Feldspar: two at 90°

Lustre

How light leaves it

Vitreous · Metallic · Waxy · Pearly · Earthy

Habit

The shape it grows in

Cubes · Prisms · Botryoidal · Bladed · Massive

Nº IV · The Free Tools

Free tools of the room

A range to orient you, in seconds.

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Streak & Acid ReferenceWhat colour does it streak?Soon
Nº V · Field Notes

On the reading of stones

  • Quartz is colourless when pure and occurs as amethyst, citrine, rose, smoky and agate — one species, six names.
  • Fluorite occurs in every colour there is, which is why purple fluorite is sold as amethyst and separated by a knife in one second.
  • Trace impurities and radiation damage change colour freely while leaving hardness, streak and density untouched.
Nº VI · The Register of Minerals

How to Identify Rocks, Minerals and Crystals

A page for each of the minerals people actually pick up, with the three field tests that settle most of them and an honest account of what a photograph cannot reach.

Quartz

Every continent — the commonest mineral in the crust

Hardness 7, no cleavage, a glassy conchoidal break and no fizz in acid. The mineral most finds turn out to be.

Read the checks

Amethyst

Brazil, Uruguay, Zambia, Madagascar, Arizona

Purple quartz, hardness 7, coloured in visible zones. The zoning is what separates it from dyed stone and glass.

Read the checks

Agate

Brazil, Uruguay, India, Mexico, Germany (Idar-Oberstein), Scotland

Banded chalcedony — quartz in microscopic fibres. Hardness 7, waxy rather than glassy, and dyed on an industrial scale.

Read the checks

Pyrite

Spain, Peru, Italy, and almost every sulphide deposit on earth

Fool's gold. Brittle where gold is malleable, streaks greenish-black where gold streaks yellow, and a quarter of gold's density.

Read the checks

Obsidian

Iceland, Mexico, Oregon, Armenia, Turkey — anywhere rhyolitic lava cooled fast

Natural volcanic glass. Not a mineral at all, strictly, and the hardest of all to separate from the manufactured kind.

Read the checks

Turquoise

Iran, the American Southwest, China, Egypt, Mexico

The most heavily faked stone in the trade. Most of what is sold as turquoise is dyed howlite, reconstituted powder or plastic.

Read the checks
All 16 minerals we read
The Journal

From the Journal

Longer, plain-English guides on the questions we are asked most — free to read.

Stone · Guide

How Accurate Are Rock Identifier Apps?

Mineral identification rests on hardness, streak and density. A photograph cannot measure any of the three — and the property it reads best is the one that proves least.

8 min readRead the guide
All guides in the Journal
The Lovenhall RegistryLovenhall Stone

Write about a stone

A specimen the instrument could not place, a test that came back ambiguous, or a mineral the register does not read yet — the house is glad to hear it.

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