WHAT IS A PRECIOUS GEM STONE

AND SEMIPRECIOUS?

A gem is a naturally occurring material desirable for

its beauty, valuable in its rarity, and

sufficiently durable to give lasting pleasure.

DIAMOND

EMERALD.

SAPPHIRE RUBY

Semi-precious stones are usually softer and less valuable, and thus not as rare as precious gems. the mineral olivine has a semi-precious variety called peridot

Peridot is one of the few gemstones that occur in

only one color, an olive green. The intensity and

tint of the green, however, depends on how much

iron is contained in the crystal structure, so the

color of individual peridot gems can vary from

yellow- to olive- to brownish-green. The most

valued color is a dark olive-green.

JADE.

JADEITE – MORE THAN $3 MILLION PER CARAT

The more intense the green, the more expensive the stone will get. The Chinese, however, also value the white jadeite with green spots. A deep blue-green jadeite that emits a translucent hue has also been discovered in recent times in Guatemala.

GARNET

AMETHYST

CITRINE

ROSE QUARTZ.

TOURMALINE.

TURQUOISE

SUNSTONE

AGAT

There are two major exceptions to the rule:

Because of their rarity are considered to be

precious Opal and Pearls.

OPALS

The main reasons for this

is the very high demand

and the fact that truly

magnificent black opals

are only a fraction of the

total black opal

production. High quality

black opal sells for around

$2,000 per carat, though

prices of $5,000 and higher

are not unheard of.

PEARLS.

It is important to distinguish where gems

are formed from where they are found. Gems are not

always found where they were formed, nor are they

formed where they're found.

Almost all gems are formed below the Earth's

surface.

WEATHERING OF ALL TYPES OF ROCKS YIELDS SEDIMENTS THAT ARE

DEPOSITED IN A WIDE VARIETY OF ENVIRONMENTS, SUCH AS STREAMS

AND RIVERS, SHORELINES, ALLUVIAL FANS, AND DELTAS

ALLUVIAL FANS

Guyana: In the first half of the 20th century

miners, employing primitive methods, recovered

significant quantities of gem-quality diamonds

from the rivers and streams. In fact the two

largest gem-quality diamonds recovered in to

date - 56.75 carats and 25.67 carats.

VALUE

The 4 C'S factors:

Color: Some colors are more desirable than

others.

Clarity: flaws (crack, inclusions) decrease the

value of a gemstone.

Cut: Poorly cut stones have much lower value.

Carat weight:

THE REASON WHY GOLD WILL TAKE THIS PATH IS BECAUSE OF THE FLOW OF WATER

DURING A STORM – A RIVER THAT IS RUNNING AT ITS NORMAL RATE OF FLOW DOES

NOT HAVE ENOUGH POWER AND FORCE TO MOVE GOLD FROM WHERE IT CURRENTLY

LIES, IT TAKES A SUBSTANTIAL STORM TO DO THAT. SO LET'S INCREASE THE HEIGHT

AND STRENGTH OF THE WATER TO STORM LEVELS/HIGH RATE OF FLOW

AS THE RIVER CONTINUES FURTHER THROUGH THE BENDS IT

ALSO DOES THE SAME THING AT THE NEXT BEND -

GOLD RUBIES AND SAPPHIRES FROM CAMBODIA RIVER.

HYDRAULICKING

THE USE OF GREASE TABLE TO

RECOVER DIAMOND

LOOK AND TAKE NOTE

LUSTRE

SCRATCH TEST

.SAMPLINGSEDIMENTTREAMS

One of the primary methods

used in diamond exploration is

stream sediment sampling

designed to search for kimberlitic

indicator minerals. The indicator

minerals may be carried

downstream for hundreds of

miles.

PYROPE GARNETCHROMIAN DIOPSIDE

This is the classical kimberlitic indicator

minerals in the field. This mineral has an

average specific gravity of 3.4 thus it can be

readily captured in a gold pan with black

sand concentrates.

CHROMIAN

ENSTATITE. PICROILMENITE

CHROMIAN SPINEL Diamond

MEGACRYSTS ALSO PROVIDE A

GOOD SOURCE FOR

INDICATOR MINERALS

PERIDOTITE NODULE FROM

KIMBERLITE. NOTE THE ROUNDED

PYROPES IN THIS SPECIMEN

THE TRADITIONAL KIMBERLITIC INDICATOR MINERALS ARE RARE TO NON-EXISTENT

IN LAMPROITE THESE MINERALS MAY BE CONSIDERED UNFORTUNATELY HAVE LOW

SPECIFIC GRAVITY, POOR RESISTANCE TO ABRASION, AND ARE POTENTIALLY

DIFFICULT TO IDENTIFY. THE BETTER INDICATORS FOR DIAMONDIFEROUS

LAMPROITE HAVE BEEN DIAMOND, AND OLIVINE.

zircon Phlogopite

K-RICHTERITE Armalcolite

PRIDERITE Magnesiochromite

العقـيــق الســـــوداني

FROTH FLOTATION