The fern leaves and other forms are 14 K overlay. The two large turquoise stones are high quality blue-green that resembles Bisbee stones. There are traces of iron pyrite in the turquoise. Additionally, there is a good size fire agate below the Bison head, and an Australian opal placed above the head.
Two pieces of vivid red coral complete the array of stones. The buckle is 4-1/2 inches wide and stands 3-1/4 inches high. With the Bison head, the buckle is 1.1 inches deep. The signature on the back consists of the initials "TH" with a small "o" on either side that I believe are not initials, but are placed there to frame the TH.
I don't know who "TH" is. However, this piece closely resembles Navajo work in style and form based on my close familiarity with Native American jewelry art for most of my 82 years. In any case the value of this buckle is more related to its materials, scope and workmanship than to its maker's registry listing. The item "4.5 X 3.2.925 Silver &14K Belt Buckle-large Bison-Turquoise-Coral-Fire Agate" is in sale since Sunday, February 2, 2020. This item is in the category "Jewelry & Watches\Handcrafted, Artisan Jewelry\Other Artisan Jewelry".
The seller is "sedonafotopro" and is located in Sedona, Arizona. 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, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Uruguay.