Guides
Each guide answers one question completely. No filler, and no advice that requires equipment you do not have.
What to Do Before You Ask Anyone to Identify a Rock
A wash, a fresh break and four photographs turn an unanswerable question into an answerable one. Most identification requests fail on the photograph alone.
4 min read
What Is This Black Shiny Rock?
Eight things account for nearly every shiny black rock. Streak colour, weight and how it breaks separate all of them in about two minutes.
3 min read
Rock, Mineral, or Neither?
A mineral is one substance with one composition. A rock is an aggregate of them. And a great deal of what gets brought in for identification is neither.
3 min read
Is This a Meteorite? Almost Certainly Not
Slag, magnetite and industrial waste account for nearly every suspected meteorite. Fusion crust, density, magnetism and the nickel test — and what rules one out instantly.
3 min read
Is There Gold in This Quartz?
Usually pyrite or mica, and both are easy to rule out in under a minute. The four tests that settle it, and what a genuine gold-bearing specimen looks like.
3 min read
Gold vs Pyrite: Six Tests That Settle It in Two Minutes
Six field tests that separate real gold from pyrite, chalcopyrite and mica — using a knife, a ceramic tile and your hands. No chemicals required.
4 min read
Calcite vs Quartz: How to Tell Them Apart Every Time
Calcite and quartz look almost identical and behave completely differently. Four tests — hardness, acid, cleavage and crystal shape — separate them in under a minute.
4 min read
Hematite vs Magnetite: The Magnet and the Streak Plate
Two black iron minerals, two tests. A magnet and a ceramic tile separate hematite from magnetite reliably — here is why, and what to do about the confusing cases.
3 min read
Jade or Serpentine? What Most Green Stone Actually Is
Most green stone sold as jade is serpentine. Four practical tests — the knife test, heft, sound and translucency — tell you which one you have.
3 min read