I think the lighter background has affected the exposure. Looking at the handle in both images, the wood handle is very dark. In the 2nd image the wood is nearly black and I would guess the wood shows different in hand. Even most black woods have grain.
There could be a couple ways to handle this.
Change to a darker background to give your camera light meter less trouble. When we shoot images in house for our web site, we had to switch from a white background to neutral gray since the white kept overwhelming the light meters in our camera and causing spot exposure issues.
Increase exposure compensation to bring out the wood but the back ground will probably be too bright.
Use software in post edit to adjust exposure but then you start running into color shift issues. It's always better to get the lighting and the image as good as you can and minimal post edit.
Throw up another light and aim it at the handle. (which would be the very first thing I would try)
You can use layers in photo software to create a composite image and this is what many/most of the pro's would do on a bigger knife. (on a smaller knife the depth of field and exposure issues are not as big of a problem) Basically, you would shoot two or three images with out moving the camera (tripod). Each image would have a different focus point. One image would focus on the handle, getting the exposure and focus correct for just the handle. Another image would do that same thing for the blade. In photo software the two images are superimposed. The blurry parts on each image are masked out and the remaining composite image is a blend of two pictures that look like one picture.
Generally, the most dramatic images done by the pro's have a distinct drop shadow either added during lighting or if the knife is "lifted" from the background (pretty common), a drop shadow is added. A nicely done drop shadow will change an image from flat and lifeless to something that looks like it want's to pop off the paper.
Jeff, that blade finish is spectactular. Just beautiful. The knife is a stunner.
As far as the picture, the only thing that seems a little off is the white balance. On the iphone you're pretty much stuck. I'm often shocked by how good my iphone pics come out, and yours is a great one.
My tips for making the most of a smartphone is to understand 3 things
1. The sensor has too many pixels... so hardly any of them are any good this means two things noise and dont crop images much. So you must please the sensor... to please the sensor it means you need as little as possible contrast in brightness, and it must be light enough that it does not decide to boost the signal with those little amplifiers... So a very even brightness in the photo, which means as said above shield or angle the blade from direct light, reflect some extra light on the handle use a background that contrast in colour not reflectance...
2. Dont use a flash, play with the hdr and dro settings, to even out the image, but it comes at a cost... noise and colour distortion
3. Support your phone hands...
4. Use the irritatingly large depth of field to your advantage...
5. Outdoors or interesting reflections are often useful