search
  • English speaking customer support only

    Toll Free - USA & Canada only:
    1-800-464-1640

    International:
    +66-39303404

  • Change Language
  • USD

Urban Mining for Precious Metals - Waste Not Want Not

Pure Gold
Pure Gold

Some cities are said to be paved with gold and this is taken literally by people known as "urban miners", who collect tiny fragments of gold and gemstone chips in dirt from the jewelry districts of cities all over the world.

Although gold and jewelry workers try their best to collect every scrap of material, by taking measures such as collecting fragments of gold from water used to wash hands, tiny pieces manage to escape and make their way into the city streets. Precious fragments may be washed down the drains by the rain, flushed down the toilet, or taken away in rubbish bins. Yet some rich pickings get into the cracks in the roads and pavements where they settle in the dirt.

In order to recover the gold and gemstone chips, several methods can be employed. Sewage sludge (the product that remains after sewage treatment) is processed in Nagano Prefecture of Japan. The Suwa Treatment Facility extracts gold from molten fly ash. The yield is said to be higher than that of the Hishikari Mine in Japan. This could be due to the amount of precision equipment manufacturers in the area. In the USA, scientists from Arizona State University surveyed sewage sludge samples from 32 different states and stated the possible value of the metals found in biosolids from a community of 1 million people to be up to US13 million per year.

Tiny Gold Flecks From Indian Street Sludge
Tiny Gold Flecks From Street Sludge

A more crude operation takes place in cities such as Bangkok, Baghdad and Kolkata, where in the early hours of the day, people gather sludge from the drains, sewers and canals of jewelry districts and either use a panning technique to painstakingly extract the gold themselves or sell the sludge to others. Some of the urban entrepreneurs who do this are impoverished people from rural villages. In some cases, they are able to collect enough gold to return to their homes with a brighter future.

Precious metals can also be extracted from scrap such as IT products. Such valuable materials are extracted from discarded electrical appliances, such as computer and mobile phone circuit boards, that are found in rubbish dumps outside cities in Japan. It is said that a ton of recycled mobile phones can produce more gold than the average ton of ore from a gold mine. The gold and other metals can be separated, melted down and then sold to jewelers. Gold is used in circuit boards because of its electrical conductivity.

Belgian recycling facility worker, Thierry Van Kerckoven is a buyer of scrap in Antwerp, where his company, Umicore, extracts 16 different metals from waste, including rhodium and gold. In addition to precious metals, increasing scarcity of rare earths has caused their value to rise. The recycling of metals would enable countries without their own supply of rare earths freedom from relying on imports from countries such as China. One problem with the recycling of metals is the low numbers of old mobile phones that are currently being handed in to recycling facilities despite the fact that people purchase new mobile phones often.

The Diamond District of Manhattan, New York
The Diamond District of Manhattan, New York

Extracting gold from sewage sludge or circuit boards may be worthwhile, but is a little labor intensive. An easier way for the average man on the street to try urban mining is to follow the example of New Yorker and freelance diamond setter, Raffi Stephanian, who collects precious metals and even cut and polished gemstones from the streets of Manhattan's diamond trading district. Mr Stephanian claims to have collected $819 worth of gold in just six days. He uses tweezers, a butter knife, a bowl and a strainer to harvest the dirt and then sift through it.

The next time you walk the streets of your home town, throw away an old mobile phone, or even flush the toilet, spare a thought for the precious materials that you may be passing by!

  • First Published: May-20-2015
  • Last Updated: January-24-2019
  • © 2005-2019 GemSelect.com all rights reserved.
    Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.
Popular Gemstones
  • Shop Sapphire Gemstones Sapphire
  • Shop Emerald Gemstones Emerald
  • Shop Ruby Gemstones Ruby
  • Shop Aquamarine Gemstones Aquamarine
  • Shop Zircon Gemstones Zircon
  • Shop Opal Gemstones Opal
  • Shop Topaz Gemstones Topaz
  • Shop Tourmaline Gemstones Tourmaline
  • Shop Garnet Gemstones Garnet
  • Shop Amethyst Gemstones Amethyst
  • Shop Citrine Gemstones Citrine
  • Shop Tanzanite Gemstones Tanzanite
All Gemstones (143)
A B C D E F G H I J K L M N O P Q R S T V Z
  • Shop Actinolite Cat's Eye Gemstones Actinolite Cat's Eye
  • Shop Agate Gemstones Agate
  • Shop Agate Geode Gemstones Agate Geode
  • Shop Almandine Garnet Gemstones Almandine Garnet
  • Shop Amazonite Gemstones Amazonite
  • Shop Amethyst Gemstones Amethyst
  • Shop Amethyst Geode Gemstones Amethyst Geode
  • Shop Ametrine Gemstones Ametrine
  • Shop Ammolite Gemstones Ammolite
  • Shop Andalusite Gemstones Andalusite
  • Shop Andesine Labradorite Gemstones Andesine Labradorite
  • Shop Apatite Gemstones Apatite
  • Shop Aquamarine Gemstones Aquamarine
  • Shop Aventurine Gemstones Aventurine
  • Shop Beryl Gemstones Beryl
  • Shop Black Opal Gemstones Black Opal
  • Shop Bloodstone Gemstones Bloodstone
  • Shop Boulder Opal Gemstones Boulder Opal
  • Shop Calcite Gemstones Calcite
  • Shop Carnelian Gemstones Carnelian
  • Shop Cat's Eye Apatite Gemstones Cat's Eye Apatite
  • Shop Cat's Eye Aquamarine Gemstones Cat's Eye Aquamarine
  • Shop Cat's Eye Augite Gemstones Cat's Eye Augite
  • Shop Cat's Eye Gemstones Gemstones Cat's Eye Gemstones
  • Shop Cat's Eye Moonstone Gemstones Cat's Eye Moonstone
  • Shop Cat's Eye Opal Gemstones Cat's Eye Opal
  • Shop Cat's Eye Scapolite Gemstones Cat's Eye Scapolite
  • Shop Chalcedony Gemstones Chalcedony
  • Shop Charoite Gemstones Charoite
  • Shop Chocolate Opal Gemstones Chocolate Opal
  • Shop Chrome Diopside Gemstones Chrome Diopside
  • Shop Chrome Tourmaline Gemstones Chrome Tourmaline
  • Shop Chrysoberyl Gemstones Chrysoberyl
  • Shop Chrysocolla Gemstones Chrysocolla
  • Shop Chrysoprase Gemstones Chrysoprase
  • Shop Citrine Gemstones Citrine
  • Shop Citrine Geode Gemstones Citrine Geode
  • Shop Color-Change Diaspore Gemstones Color-Change Diaspore
  • Shop Color-Change Fluorite Gemstones Color-Change Fluorite
  • Shop Color-Change Garnet Gemstones Color-Change Garnet
  • Shop Color-Change Sapphire Gemstones Color-Change Sapphire
  • Shop Coral Gemstones Coral
  • Shop Demantoid Garnet Gemstones Demantoid Garnet
  • Shop Dendritic Agate Gemstones Dendritic Agate
  • Shop Diamond Gemstones Diamond
  • Shop Emerald Gemstones Emerald
  • Shop Enstatite Gemstones Enstatite
  • Shop Fire Agate Gemstones Fire Agate
  • Shop Fire Opal Gemstones Fire Opal
  • Shop Fluorite Gemstones Fluorite
  • Shop Fossil Coral Gemstones Fossil Coral
  • Shop Garnet Gemstones Garnet
  • Shop Golden Beryl Gemstones Golden Beryl
  • Shop Grandidierite Gemstones Grandidierite
  • Shop Grossularite Garnet Gemstones Grossularite Garnet
  • Shop Hawk's Eye Gemstones Hawk's Eye
  • Shop Hematite Gemstones Hematite
  • Shop Hemimorphite Druzy Gemstones Hemimorphite Druzy
  • Shop Hessonite Garnet Gemstones Hessonite Garnet
  • Shop Hiddenite Gemstones Hiddenite
  • Shop Howlite Gemstones Howlite
  • Shop Idocrase Gemstones Idocrase
  • Shop Imperial Topaz Gemstones Imperial Topaz
  • Shop Iolite Gemstones Iolite
  • Shop Jade Gemstones Gemstones Jade Gemstones
  • Shop Jadeite Gemstones Jadeite
  • Shop Jasper Gemstones Jasper
  • Shop Kornerupine Gemstones Kornerupine
  • Shop Kunzite Gemstones Kunzite
  • Shop Kyanite Gemstones Kyanite
  • Shop Labradorite Gemstones Labradorite
  • Shop Lapis Lazuli Gemstones Lapis Lazuli
  • Shop Larimar Gemstones Larimar
  • Shop Malachite Gemstones Malachite
  • Shop Malaya Garnet Gemstones Malaya Garnet
  • Shop Mali Garnet Gemstones Mali Garnet
  • Shop Maw-Sit-Sit Gemstones Maw-Sit-Sit
  • Shop Moonstone Gemstones Moonstone
  • Shop Morganite Gemstones Morganite
  • Shop Moss Opal Gemstones Moss Opal
  • Shop Mother of Pearl Gemstones Mother of Pearl
  • Shop Mystic Quartz Gemstones Mystic Quartz
  • Shop Mystic Topaz Gemstones Mystic Topaz
  • Shop Nuummite Gemstones Nuummite
  • Shop Obsidian Gemstones Obsidian
  • Shop Opal Gemstones Opal
  • Shop Opal Doublet Gemstones Opal Doublet
  • Shop Opal in Matrix Gemstones Opal in Matrix
  • Shop Pearl Gemstones Pearl
  • Shop Peridot Gemstones Peridot
  • Shop Pietersite Gemstones Pietersite
  • Shop Prehnite Gemstones Prehnite
  • Shop Pyrite Gemstones Pyrite
  • Shop Pyrope Garnet Gemstones Pyrope Garnet
  • Shop Quartz Gemstones Quartz
  • Shop Quartz Cat's Eye Gemstones Quartz Cat's Eye
  • Shop Quartz With Marcasite Gemstones Quartz With Marcasite
  • Shop Rainbow Moonstone Gemstones Rainbow Moonstone
  • Shop Rainbow Pyrite Gemstones Rainbow Pyrite
  • Shop Rhodochrosite Gemstones Rhodochrosite
  • Shop Rhodolite Garnet Gemstones Rhodolite Garnet
  • Shop Rhodonite Gemstones Rhodonite
  • Shop Rose Quartz Gemstones Rose Quartz
  • Shop Ruby Gemstones Ruby
  • Shop Ruby in Fuchsite Gemstones Ruby in Fuchsite
  • Shop Ruby-Zoisite Gemstones Ruby-Zoisite
  • Shop Rutile Quartz Gemstones Rutile Quartz
  • Shop Sapphire Gemstones Sapphire
  • Shop Scolecite Gemstones Scolecite
  • Shop Seraphinite Gemstones Seraphinite
  • Shop Serpentine Gemstones Serpentine
  • Shop Sillimanite Gemstones Sillimanite
  • Shop Sillimanite Cat's Eye Gemstones Sillimanite Cat's Eye
  • Shop Smithsonite Gemstones Smithsonite
  • Shop Smoky Quartz Gemstones Smoky Quartz
  • Shop Snowflake Obsidian Gemstones Snowflake Obsidian
  • Shop Sodalite Gemstones Sodalite
  • Shop Spectrolite Gemstones Spectrolite
  • Shop Spessartite Garnet Gemstones Spessartite Garnet
  • Shop Sphalerite Gemstones Sphalerite
  • Shop Sphene Gemstones Sphene
  • Shop Spinel Gemstones Spinel
  • Shop Star Diopside Gemstones Star Diopside
  • Shop Star Garnet Gemstones Star Garnet
  • Shop Star Gemstones Gemstones Star Gemstones
  • Shop Star Lemon Quartz Gemstones Star Lemon Quartz
  • Shop Star Moonstone Gemstones Star Moonstone
  • Shop Star Rose Quartz Gemstones Star Rose Quartz
  • Shop Star Ruby Gemstones Star Ruby
  • Shop Star Sapphire Gemstones Star Sapphire
  • Shop Star Sunstone Gemstones Star Sunstone
  • Shop Strawberry Quartz Gemstones Strawberry Quartz
  • Shop Sugilite Gemstones Sugilite
  • Shop Sunstone Gemstones Sunstone
  • Shop Tanzanite Gemstones Tanzanite
  • Shop Tiger's Eye Gemstones Tiger's Eye
  • Shop Tiger's Eye Matrix Gemstones Tiger's Eye Matrix
  • Shop Topaz Gemstones Topaz
  • Shop Tourmaline Gemstones Tourmaline
  • Shop Tsavorite Garnet Gemstones Tsavorite Garnet
  • Shop Turquoise Gemstones Turquoise
  • Shop Variscite Gemstones Variscite
  • Shop Zircon Gemstones Zircon
Main Categories
  • New Arrivals
  • Gemstone Lots
  • Gemstone Lots - By Piece
  • Matched Pairs
  • Cabochon Gems
  • Drilled Gems, Briolettes and Beads
  • Gemstone Carvings
  • Fancy Gemstones
  • Star Gemstones
  • Unheated Sapphire
English speaking customer support only

Toll Free - USA & Canada only:
1-800-464-1640

International:
+66-39303404

Save Money
No shipping Fees for Additional Items!
$8.90 Worldwide Shipping

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
Size and Weight

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart