how do you identify raw uncut gemstones?

Answer 1

There are several ways to help identify uncut gemstones:

1) Crystal Habit of the rough
Different gemstones come in different crystal habits. For e.g. Sapphires are usually found as hexagonal bipyramids, Garnets come in cute rhombic shapes like dodecahedrons, Calcite in a oblique oblong shape, Emeralds in hexagonal prisms and so on. If you can recognise the crystal habit of the uncut stones, you would be one step closer to identifying the gemstone.

2) Specific Gravity (Density)
You can either make your own hydrostatic machine (google it!) or use one that is specially made for gemstones. It is simply a ratio between the weight of the gemstone in the air versus in the water. This is a fairly indicative test. For e.g. Sapphires & rubies will be 4, Diamond 3.52, Jadeite 3.33 and so on. Expect some variations if your rough has many inclusions or has a lot of foreign material/rock in/on it.

3) Observe Inclusions
If you are an experienced gemologist, you might be able to loupe the rough material and identify the gemstone based on its inclusions. If you have access to advanced lab equipment - better still. Some inclusions are typical of certain stones. For e.g. Corundum (ruby & sapphire) often has tiny needles intersecting at 60/120 degrees. A common inclusion in Tourmaline is liquid that comes in elongated irregular forms.

4) General Observation
Does it feel heavy? Does it have heft? Is it hard or not so hard? Do a scratch test. Is it tough? Using a small bit of rough, attempt to break it. How does it fracture? Does it cleave? or is the fracture choncoidal? splintery? Different gemstones react differently. For e.g. Calcite and Fluorite will cleave perfectly, Jade will show a splintery fracture. Most other gems will give a conchoidal fracture effect.

A good place to start to learn about rough gems is this mineralogy site:http://www.mindat.org It's the largest internet mineralogical database.

Hope that helps!

Answer 2

Uncut Gemstones

Answer 3

This Site Might Help You.

RE:
how do you identify raw uncut gemstones?

Answer 4

It really depends on what type of gemstone, and what kind of formation your looking in. There are alot of different types of gemstones, environements to find them in, and what kind of formation.

Answer 5

get a high quality photo book , it will have stones hardness scale .and pictures. Once you get into lapidary more you will find it quite useful as well .

Answer 6

they look ugly as ****