There are two markets in this category and they value almost opposite things.
The two rooms
Collectors pay for species, locality, crystal form, matrix and condition of the terminations. They want the data.
Decorative buyers pay for size, colour and how it looks on a shelf. They want the object.
The same specimen can be a good buy for one and an expensive mistake for the other. Say which you think you have, and give the data either way — a decorative buyer loses nothing from a locality, but a collector cannot bid without it.
What moves the number
- Species and locality, stated
- Crystal form and whether terminations are intact
- Size and weight, measured
- Treatment, declared
- Matrix and presentation
- Whether a damaged point has been repaired or reglued
Where to start
Tumbled stones and common decorative pieces: low start, run in lots, keep the pace up. This is volume.
Specimens with a species and a locality: start sensibly, and use a reserve if a quiet night would hurt.
Do not price on claims
Pricing a stone on what it is said to do for a person, rather than what it is, is building a number on a sentence you cannot support. Price the mineral.
Delivery
Heavy, and heavier than it looks. Weigh before you quote a combined rate on a multi-piece win. How delivery is charged.
Questions people ask
Should I split a parcel of tumbles?
Sell them as lots by type. Singles are rarely worth the camera time.
Does matrix add value?
To collectors, often yes — a crystal on its original matrix can be worth more than the same crystal removed.
How do I price something unidentified?
Low start, honest description, and let the room identify it. Frequently somebody will.