RAW is photo format where data from digital cameras sensor is saved without extensive processing. Normal JPEG photo is color temperature adjusted, noise cancelled, sharpened, cropped, compressed and possibly even more processed.
RAW is what the camera sensor sees. RAW file contains information about the shooting conditions so RAW photo editors can make first attempt to create good looking photo based on that. But you have freedom to use your photo editor tools to create the photo you desire as RAW file has more original information than JPEG can have.
RAW file shot with Silver B&W Camera is always a full color version of the photo. Any black and white conversion settings you applied when shooting where used to create the JPEG file. But the RAW version is the original full color data from camera sensor.
RAW format is saved as .dng file with combined JPEG format .jpg file. Your devices photo gallery shows the .jpg image but if you have RAW capable photo editor it can access the RAW data from .dng file.
On Mac computers Photos application can be used to export the photo to a separate .jpg and .dng files.
RAW files are usually much larger than JPEG files. JPEG photo of 2 MB can easily be RAW file of 12 MB or more.
When using RAW mode some camera functions are limited. These limitations are imposed by underlying hardware and operating system limitations and some are natural to RAW format.