Intensity has no affect on whether or not the photoelectric effect occurs. The determining property is frequency and since frequency and wavelength are inversely proportional, wavelength matters as well. If a frequency of light can't cause the photoelectric effect to happen, no matter what the intensity is, the light can't make it happen.
I hope this helps. Let me know in the comments if anything is unclear.
we're the rest of the question
A grey coloured rock with amphibole and intermediate plagioclase like an andesine would classify as an intermediate rock by Bowen's Reaction Series and by the classification of igneous rocks would probably be like a diorite which is intermediate between a gabbro and a granite. A diorite essentially has no quartz but has the silicates amphibole (like hornblende), mica perhaps a little pyroxene and andesine plagioclase.
Is a solid? has strong intermolecular forces?