The material from the Gilbert Nevada Turquoise mine has a dark to medium brown matrix that can even go into a reddish brown. This Turquoise almost has a Bisbee look to it if you have seen Bisbee in Quarts.
The best way to know the difference is to have bought it from the miner unless you are a real expert on Turquoise varieties. Having said that, we have even seen so called Turquoise experts make mistakes. The Gilbert Turquoise Mine is a wonderful example of American Turquoise from Nevada. This item is in the category "Jewelry & Watches\Ethnic, Regional & Tribal\Bracelets & Charms".
The seller is "joseeligogarciaciachino" and is located in this country: US. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech Republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South Africa, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Norway, Saudi Arabia, United Arab Emirates, Qatar, Kuwait, Bahrain, Republic of Croatia, Malaysia, Chile, Colombia, Costa Rica, Panama, Trinidad and Tobago, Guatemala, El Salvador, Honduras, Jamaica, Antigua and Barbuda, Aruba, Belize, Dominica, Grenada, Saint Kitts-Nevis, Saint Lucia, Montserrat, Turks and Caicos Islands, Barbados, Bangladesh, Bermuda, Brunei Darussalam, Bolivia, Egypt, French Guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman Islands, Liechtenstein, Sri Lanka, Luxembourg, Monaco, Macau, Martinique, Maldives, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Dominican Republic.