About RockHoundry

Rockhounding rewards patience — a good eye for a promising ledge, a streak plate and a loupe, and a handful of simple tests that turn an unlabeled rock into an identified mineral. The trouble is that most of those tests involve arithmetic or reference tables that are easy to get wrong in the field: is that specific-gravity reading closer to quartz or calcite? How many days does this batch really need in the coarse-grit barrel? Which crystal system does a cell with these edge lengths and angles actually belong to? RockHoundry is built to answer exactly those questions, quickly, from a phone in the field or a workbench at home.

Rather than long essays you have to wade through, the site is a set of small, single-purpose calculators, each aimed at one real task. The Mohs Hardness Estimatornarrows a specimen’s hardness down to a range from simple scratch tests against a fingernail, a coin, glass, and a steel file. The Specific Gravity Calculator turns an air-and-water weighing into a density figure and a shortlist of minerals that commonly match it. The Crystal System Identifier classifies a unit cell from its edge lengths and angles into one of the seven crystal systems. The Tumbling Grit Schedule Calculator builds a stage-by-stage rotary or vibratory tumbling plan sized to a rock’s hardness. The UV Fluorescence Guide matches an observed glow under longwave or shortwave UV light against minerals known to fluoresce that color, and the Specimen Weight & Size Estimator predicts a rough specimen’s weight from its measured dimensions and a chosen mineral’s density.

Alongside the calculators, the blog and learnsection cover field craft and identification basics — how to read a streak, when a grit size actually matters, how crystal habit differs from crystal system, and what belongs in a field bag — and the Museum of Minerals is a browsable collection of crystals, gemstone rough, the agate and quartz family, and fossils, with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.

A few things worth stating plainly. RockHoundry is independent and not affiliated with any gem dealer, appraiser, laboratory, or mining company — this site is for hobby identification and field craft education only, not for pricing, grading, investment decisions, or a substitute for lab testing. It is supported by advertising, which is how the tools stay free with no account required. The calculators are field aids: they show their working and round for readability, but a definitive identification of an unusual or valuable specimen should be confirmed by a qualified mineralogist or gemologist with proper equipment. If a tool looks wrong, or there’s a calculator you wish existed, the contact page is the place to tell us.