Reflective shape changing object pacing our vehicle to the south

We noticed a reflective object hovering over a small mountain to the south of the I-10 freeway as we drove eastward. We then noted that it appeared to pace our vehicle traveling at approximately 70 mph as we headed on I-10 East. We were driving to Texas. This object changed shape several times, at times appearing disc-like, then sort of cigar shaped. It seemed to turn sometimes, looking whitish, then silvery and glinting the sun’s rays at times, as well. There appeared to be a haze of light encircling this object. We watched it until it vanished and we aren’t sure where it went. One moment it was there, the next, just gone. We watched this object for approximately 50-55 minutes and took a photo from the passenger seat as best we could in a moving vehicle, as we did not feel comfortable stopping to get a better look.