How to add a new kind of materials?

Game Talk The Toolbox
1

I am trying to add a new kind of material to this game,and the new material had been added to materials.json,but when I load the game,it show the debug message that said invoild materials…
{
“type”: “material”,
“ident”: “nanometer_fabric”,
“name”: “Nanometer Fabric”,
“density”: 10,
“specific_heat_liquid”: 0.82,
“specific_heat_solid”: 0.45,
“latent_heat”: 273,
“soft”: true,
“bash_resist”: 8,
“cut_resist”: 8,
“acid_resist”: 8,
“fire_resist”: 8,
“elec_resist”: 8,
“chip_resist”: 22,
“repaired_with”: “alloy_sheet”,
“salvaged_into”: “alloy_sheet”,
“dmg_adj”: [ “ripped”, “torn”, “shredded”, “tattered” ],
“bash_dmg_verb”: “ripped”,
“cut_dmg_verb”: “cut”,
“burn_products”: [ [ “nanometer_fabric”, 1 ] ],
“burn_data”: [ { “immune”: true }, { “immune”: true }, { “immune”: true } ]
},
{
“type”: “material”,
“ident”: “nanometer_fabric_rigid”,
“name”: “Rigid Nanometer Fabric”,
“density”: 10,
“specific_heat_liquid”: 0.82,
“specific_heat_solid”: 0.45,
“latent_heat”: 273,
“bash_resist”: 10,
“cut_resist”: 10,
“acid_resist”: 10,
“fire_resist”: 10,
“elec_resist”: 10,
“chip_resist”: 25,
“repaired_with”: “alloy_sheet”,
“salvaged_into”: “alloy_sheet”,
“dmg_adj”: [ “marked”, “dented”, “scarred”, “broken” ],
“bash_dmg_verb”: “ripped”,
“cut_dmg_verb”: “cut”,
“burn_products”: [ [ “nanometer_fabric_rigid”, 1 ] ],
“burn_data”: [ { “immune”: true }, { “immune”: true }, { “immune”: true } ]
}