X, A, 1 Smith, Edding field, Fanning: Philippine Minerals 87 



or less amorphous masses in a few igneous rocks. It has no 

 economic value. 



Galena — PbS. 



Galena is found in veins only. It is lacking in the walls. 

 Galena was formed generally later than pyrite. As a rule, it is 

 crystallized. It is associated with zinc and pyrite in quartz 

 veins, rarely in calcite veins. It frequently carries silver, but 

 rarely gold. It is nearly always primary. Galena is resistant 

 to decomposition. This mineral is found in veins in Suyoc, 

 Mountain Province; in Batangas; Cebu; Marinduque; Paracale; 

 and Surigao. During the Spanish regime galena was mined to a 

 limited extent in Cebu, but is not mined at the present time. 



Garnet — Complex silicates with Fe, Mg, Mn, and Ca as inter- 

 changeable bases. 



The common species, andratite, occurs rarely in the Philippines 

 as minute wine-red granules in a rock from Bulacan, Luzon. It 

 has no economic value. 



Gilsonite — Complex hydrocarbon. 



Gilsonite is found in the northern part of Leyte Province 

 adjacent to petroleum seeps in Miocene shale and sandstone. 

 There is no production in the Philippines, but the Leyte deposit 

 is being explored. 



Gold — Au (metallic). 



Gold occurs associated with pyrite and rarely with galena. It 

 usually occurs as metallic gold in quartz and in calcite veins as 

 wires, plates, grains, and crystals; abundantly distributed in 

 placer as perfect crystals, wires, and rounded grains; and is 

 occasionally found as nuggets weighing from 10 to 30 grams. 

 Traces of gold are found in most rocks carrying pyrite. Gold is 

 found in paying quantity in veins in Suyoc and Baguio, Mountain 

 Province; Paracale and Mambulao, Ambos Camarines; and Aro- 

 roy, Masbate. It is found in paying quantity in placer in Suyoc, 

 Mountain Province; Peiiaranda district, Nueva Ecija; Umaeri, 

 Tayabas ; Paracale, Mambulao, and Malaguit, Ambos Camarines ; 

 Cansuran, Surigao ; Hibong River, and other localities along the 

 Agusan River, Mindanao ; in Misamis Province ; and in Mindoro. 



Graphite — C. 



Graphite is reported as occurring in "graphite clay" in 

 Bulacan. 



