That's a new item's type in Alpha 3.5x. You may need to do something to gain one and by using it, learn a new crafting recipe.
“Learn to craft the Safety Box with Manganese Steel Bar, Steel Plate, and Copper Bar. The Safety...Safety Box (Book)
“Learn to craft an Umbrella with Spine, Copper Bars, and Fiber Cloth. Received as a reward from...Umbrella (Book)
“Learn to craft the Blade of Malice with the Enhanced Bronze Sword, Venom, and Mucus. It can be...Blade of Malice (Book)
“Learn to craft the Yellow Sapphire Necklace with the Topaz and Wild Cocoon. Ginger will mail you...Yellow Sapphire Necklace (Book)
“Learn to craft the Sapphire Ring with the Sapphire, Stainless Aluminum,... Found in a chest in...Sapphire Ring (Book)