Line a rimmed baking sheet with parchment paper and lightly coat with nonstick spray or line baking sheet with silicon mat.
Crush the saffron threads with the back of a spoon in small bowl. Soak saffron in rose water in a small bowl and set aside.
Bring sugar, corn syrup, honey, and 2 tablespoons of water to a boil in a medium saucepan fitted with candy thermometer over medium heat. Stir to mix and dissolve sugar. Cook, swirling occasionally, until thermometer registers 290°F, about 5 minutes.
Mix in almonds, butter, and kosher salt and cook, stirring often, until almonds are golden, butter is absorbed, and thermometer registers 300°F, about 2 minutes. Vigorously mix in baking soda, then saffron rose water mixture. Caramel will bubble at first but then look smooth and creamy.
Immediately pour onto prepared baking sheet and spread out as thin as possible with oiled spatula or by tilting baking sheet, work quickly. Sprinkle pistachios, rose petals, and sea salt over brittle. Let cool, then break into bite-size pieces.