Collecting guide

How to Collect Minerals

Mineral specimens, arranged by the ten classes of the Nickel-Strunz classification.

A mineral specimen is only as good as its label. Two fine quartz crystals look alike; the one with a precise, documented locality is a scientific record, the other a decoration. Mineral collecting is the art of combining beautiful specimens with exact data.

Getting Started

ordicio sorts minerals into the ten chemical classes of the Nickel-Strunz system used by the International Mineralogical Association (IMA) and by mindat:

Native elements, such as gold, silver, copper and sulfur.
Sulfides and sulfosalts, such as pyrite and galena.
Halides, such as fluorite and halite.
Oxides and hydroxides, such as quartz, hematite and corundum.
Carbonates and nitrates, such as calcite, rhodochrosite and malachite.
Borates, sulfates and phosphates, such as baryte, gypsum and apatite.
Silicates, the largest class, split by crystal structure.
Organic compounds, a small class of minerals such as whewellite.

Collect by locality (all minerals of one mine or region), by species or class, by crystal habit, or by size - thumbnails and micromounts take little space and can be of world class.

What to Record

Species: the IMA-approved name, with associated minerals on the same specimen.
Locality: as precisely as possible - mine, level or pocket, district, region, country - and the date it was found if known.
Size class and dimensions: micromount, thumbnail, miniature, small cabinet or cabinet, and the measurements.
Physical properties: crystal system, lustre, hardness, fluorescence, and radioactivity where it applies.
Provenance: earlier collections, dealers and their labels. Keep old labels; they often hold information found nowhere else.
Treatments and repairs: glued crystals, oiled or irradiated specimens.

Care and Storage

Store specimens in individual boxes or trays with their label, so labels never get separated. Some minerals are sensitive to light (realgar, many silver minerals), others to humidity (halite) or loss of water (some sulfates). Radioactive specimens need ventilated storage away from living spaces.

Mistakes to Avoid

Writing “Germany” when the label of the dealer said the exact mine.
Cleaning specimens with acids without knowing which minerals the matrix holds.
Trusting a trade name instead of the species name.

Kinds of Minerals

Native ElementsStrunz class 1 - metals and non-metals occurring uncombined, e.g. gold, copper, sulfur, diamond.
Sulfides & SulfosaltsStrunz class 2 - e.g. pyrite, galena, sphalerite, chalcopyrite.
HalidesStrunz class 3 - e.g. fluorite, halite.
Oxides & HydroxidesStrunz class 4 - e.g. quartz, hematite, corundum, cassiterite, goethite.
Carbonates & NitratesStrunz class 5 - e.g. calcite, malachite, azurite, rhodochrosite.
BoratesStrunz class 6 - e.g. borax, colemanite, ulexite.
Sulfates & RelatedStrunz class 7 - sulfates, chromates, molybdates and tungstates, e.g. baryte, gypsum, wulfenite, crocoite.
Phosphates & RelatedStrunz class 8 - phosphates, arsenates and vanadates, e.g. apatite, pyromorphite, vanadinite, turquoise.
SilicatesStrunz class 9 - the largest class, divided by how the silicate tetrahedra are linked. Nesosilicates, Sorosilicates, Cyclosilicates, Inosilicates, Phyllosilicates, Tectosilicates
Organic CompoundsStrunz class 10 - e.g. whewellite, mellite; amber is not a mineral and goes to Organic gems.

The Data Sheet for Minerals

The 44 fields worth recording for minerals, grouped as in the ordicio app.

Identification

Species Text: Mineral species as approved by the IMA (main species first), or the material for pearls and organic gems, e.g. Quartz, Corundum, Beryl.
Variety Text: Variety or trade name, e.g. Amethyst, Ruby, Emerald, Rose quartz.
Associated minerals Text: Other minerals on the specimen.
Chemical formula Text: Ideal formula as given by the IMA or mindat, e.g. SiO2, CaCO3.
Strunz code Text: Nickel-Strunz (10th edition) class code, e.g. 4.DA.05 for quartz.
Reference link Link: Web page about this object or its reference entry (catalogue, database, sale).

Properties

Physical properties of the species and this specimen.

Crystal system Choice: Crystal system of the species.
Cubic (isometric)
Tetragonal
Hexagonal
Trigonal
Orthorhombic
Monoclinic
Triclinic
Amorphous
Crystal habit Text: Shape of the crystals or aggregate, e.g. prismatic, cubic, botryoidal, acicular, twinned.
Colour Text: Colour or colours as seen in daylight, main colour first.
Luster Choice: How the surface reflects light.
Metallic
Submetallic
Adamantine
Vitreous
Resinous
Pearly
Silky
Greasy
Waxy
Dull / earthy
Transparency Choice: How much light passes through.
Transparent
Translucent
Opaque
Mohs hardness Number, 1 to 10: Hardness on the Mohs scale (1 talc to 10 diamond).
Specific gravity Number: Density relative to water.
Streak Text: Colour of the powder on an unglazed porcelain plate.
Cleavage / fracture Text: How the mineral breaks, e.g. perfect cleavage in three directions, conchoidal fracture.
Fluorescence Text: Response to ultraviolet light, e.g. LW bright green, SW none.
Radioactive Choice: Whether the specimen is measurably radioactive (e.g. uraninite, autunite).
No
Yes (store and label accordingly)

Specimen

Size class Choice: Size class by the largest dimension as used by collectors and dealers (limits differ slightly between sources).
Micromount (needs magnification)
Thumbnail (up to about 3 cm)
Miniature (about 3 to 5 cm)
Small cabinet (about 5 to 10 cm)
Cabinet (about 10 to 20 cm)
Large cabinet / museum (over 20 cm)
Specimen form Choice, or your own: What the specimen consists of.
Single crystal (floater)
Crystal group
Crystals on matrix
Massive / rough
Slab or polished face
Sphere / carving
Height (cm) Number: Height, measured upright as the object is meant to stand or hang.
Width (cm) Number: Width, measured from the front.
Depth (cm) Number: Depth, measured from front to back.
Weight (g) Number: Weight of the object (without stand, frame or holder unless noted).
Treatment Text: Cleaning, acid treatment, oiling, dyeing, irradiation, heating, stabilising or repairs.

Origin

Where the specimen comes from.

Locality Text: Exact find site, as specific as possible, e.g. quarry, mine and level, beach, outcrop.
Region Text: State, province, county or district of the locality.
Country Text: Country of origin or issue, by its usual English name (historic states as named at the time, e.g. Kingdom of Bavaria).
Coordinates Place: Geographic position of the locality (keep private for sensitive sites).
Collected by Text: Person who collected or excavated the specimen.
Collection date Date: Date the specimen was collected in the field.
Labels Text: Old dealer and collection labels with their numbers, transcribed.

Condition

Condition Choice: Overall condition in plain terms; domains with an established grading scale use that scale instead.
Mint / as new
Excellent
Very good
Good
Fair
Poor
Condition notes Text: Faults, wear and damage in detail.

Acquisition

How and when the object came into the collection.

Acquisition date Date: Date the object came into the collection.
Acquisition method Choice, or your own: How the object came into the collection.
Purchase
Auction
Gift
Inheritance
Exchange / trade
Self-collected / found
Commission
Acquired from Text: Seller, auction house (with sale and lot number), donor or place where it was found.
Purchase price Amount: Price paid including fees and premiums.
Provenance Text: Earlier owners and the object's history, oldest first, with sources (labels, invoices, sale catalogues).

Value

Estimated and insured value.

Estimated value Amount: Current market value as estimated.
Valuation date Date: Date of the current value estimate.
Valuation basis Choice: What the estimated value is based on.
Own estimate
Recent sales / auction results
Dealer offer
Catalogue value
Professional appraisal
Insurance valuation
Insured value Amount: Sum the object is insured for.

Collection record

Your own inventory data.

Inventory number Text: Your own number or label for the object, e.g. C-0042, as written on its label or album page.
Storage location Text: Where the object is kept, e.g. room, cabinet, drawer, album and page, box.

Standards and References

The data sheets follow the standards collectors, dealers and museums use:

Nickel-Strunz classification, 10th edition (classes 1 to 10); IMA list of mineral species; mindat.org localities
AFMS and dealer usage for specimen size classes (thumbnail, miniature, small cabinet, cabinet)
IUGS classification of igneous rocks (QAPF), standard sedimentary/metamorphic classes
Meteoritical Society nomenclature, Meteoritical Bulletin Database; shock stages S1 to S6 (Stoeffler et al.), weathering grades W0 to W6 (Wlotzka)
GIA diamond grading (colour D to Z, clarity FL to I3, cut); CIBJO / LMHC nomenclature for gem treatments; pearl value factors

Updated October 24, 2026