Indeed, when it comes to quartz, that is true. However, the explanations of quartz and samadhi that have been passed down since ancient times seem to be often misunderstood.

According to ancient traditions, it is said that in the state of samadhi, quartz reflects the object, and that is indeed true. However, in reality, consciousness itself is "space," so it is a story that the space as a whole purely reflects the object like quartz. If you simply accept the ancient traditions, you may misunderstand that a small stone like quartz is like the heart of samadhi, but in reality, in the state of samadhi, consciousness changes, or rather, the normal thinking consciousness is basically stopped, but it can be moved. The true "I" is the consciousness of the atman behind it. And that consciousness of the atman is, in a sense, "the whole" or "space" itself. So, it is an analogy of "the whole" or "space" that purely reflects the object like quartz.

Therefore, as I have said repeatedly, it is not a story about a "quartz stone" that fits in the palm of your hand, but a story about the nature of space itself, the nature of consciousness, that purely reflects the object like quartz.

And in that state, in yoga, it is said that "subject, object, and action" become one. This is, of course, a natural thing. Consciousness is the atman itself, which is "the whole." Therefore, all of one's "actions," "objects," and "movements" are included in "the whole" or "space," so it is natural that they become one. Therefore, from the perspective of consciousness as atman, all three are recognized as belonging to the same layer, because consciousness as atman is the underlying one. Our normal thinking consciousness is slightly lower, and because it is lower, from the perspective of atman, these three are recognized as belonging to the same level, and that is what is metaphorically called "becoming one."

In Japanese, these three are translated in various ways, and according to explanatory books, it is often said that "subject, object, and action" become one, or that "what is known, what is known, and the act of knowing" become one. While that may be true, my feeling is that the reality is slightly different.

As an explanation, there is an interpretation that the subject or the one who knows is Atman (true self), the object or the one who is known is the object, and the action or the act of knowing become one, and this can also be interpreted as such, although it is essentially the same. In this interpretation, the consciousness as Atman (true self) is universal and full, and it is space itself, so it naturally includes the object (the one who is known) and the action (the act of knowing).

However, in reality, Atman (true self) is neither the subject nor the object, so it seems more straightforward to interpret that these three exist in the lower layer of Atman (true self).

Things are simple, and essentially it is oneness, so these three things do not actually exist, but it is all a bluff.

And, the nature of Brahman (Atman, true self) also has the property of reflecting objects purely like a crystal, and since it is Brahman, it is of course "full" everywhere in space, and that is what is being referred to as the property of the "full" Brahman.

And, becoming aware of that is Samadhi. When one's consciousness becomes quiet and silent, and one escapes from the state of illusion of ordinary conscious awareness, the consciousness of Atman (true self), which is the original consciousness, begins to appear, and that state is called Samadhi.