Why are meteorite slices sold by the gram?
Because meteorites vary hugely in rarity and size, sellers often price them per gram, adjusting for type, quality, crust and history.
Meteorites are often priced by weight, usually per gram, because this provides a simple way to compare specimens of the same meteorite.
How it works. A dealer might set a price per gram for a particular meteorite, depending on its type, rarity and demand. A larger slice or fragment costs more in total but may cost less per gram than a tiny one. Very small pieces often cost more per gram, because each requires handling, labelling and packaging.
Factors that affect price per gram. - Rarity of the type. Common ordinary chondrites are usually the least expensive; Martian, lunar and rare achondrites are much more expensive. - Availability. Meteorites with large total known weights are generally cheaper than those with only a few grams known. - Fall versus find. Witnessed falls often command higher prices, especially historic ones. - Specimen type. Complete crusted individuals, oriented specimens and attractive etched or polished slices may sell for more per gram than broken fragments. - Quality and condition. Fresh, unweathered specimens with good crust and visible features are more desirable. - Provenance. Well-documented specimens from famous collections may be valued higher.
Exceptions. Some specimens are priced individually rather than by weight, such as museum-quality pieces, specimens with exceptional features, or those with special history.
Buyer advice. Compare similar specimens from different sellers. Remember that the cheapest price per gram is not always the best value if the specimen lacks documentation or is poorly prepared.