This is the big question. The answer depends entirely on you are playing:
Ensure the X-Ray pack is at the top of your Selected Resource Packs list. If another pack is above it, those textures will override the transparency. Conclusion x ray 112 2 resource pack
Most survival and factions servers consider X-Ray a bannable offense . Many servers use "Anti-Xray" plugins that turn stone into fake ore clusters to confuse the pack. Use it at your own risk. Troubleshooting Common Issues This is the big question